NEED HELP 2002 Chevy Trailblazer no crank

[mrrsm]

...and that leads us back to your Quite Excellent Photos... "Occam's Razor" bears out that "The Simplest Explanation of any problem is almost 99.99% Correct..." The Two locations that draw attention are:

(1) Re-Visit the Cut Wires and Repairs for issue that the Butt-Connectors can hide since soldering wires is the only Best Practice to follow for power sensitive circuits that emanate from the Ignition-Starter Circuit.

(2) Even without any signs of Rodent Predation...There are Under-Hood Nesting materials present in those photos showing that either Mice or Rats dragged that stuff up and around the Fuse Block, elevated above predators. Un-Bolting the Upper Fuse Block from the Lower Harness connectors and looking things over around there with a Bright Flashlight can often show locations of Chewed Through Wiring not visible in plain sight.

 

[BlueDazing]

Almost but not quite what I suggested. You determined which pin on the fuse block has 12v ... good. I then asked for you to take an impedance measurement (resistance) on the other pin (to ground). The reason for doing it this way is that if you take a impedance measurement on a powered pin, you can destroy your meter.... so you need to know which pin is powered and which is not. Further, for the impedance test, the key is OFF. You are not looking for voltage, you are looking for circuit continuity to ground like conditions.

Having said this, your voltage measurements during the start attempt seem "strange" / low.

Almost but not quite what I suggested. You determined which pin on the fuse block has 12v ... good. I then asked for you to take an impedance measurement (resistance) on the other pin (to ground). The reason for doing it this way is that if you take a impedance measurement on a powered pin, you can destroy your meter.... so you need to know which pin is powered and which is not. Further, for the impedance test, the key is OFF. You are not looking for voltage, you are looking for circuit continuity to ground like conditions.

Having said this, your voltage measurements during the start attempt seem "strange" / low.

My bad, I'm a noob at this.

During the impedance measurement, the resistance measured was jumping around at contact, (got as high as 18ko) but always levels off at 1.20ko. (I had it set to 20k)

Also, during the crank, the 12v socket for fuse #17 was actually reading around 12.20v, but I just rounded it off.

 

[BlueDazing]

...and that leads us back to your Quite Excellent Photos... "Occam's Razor" bears out that "The Simplest Explanation of any problem is almost 99.99% Correct..." The Two locations that draw attention are:

(1) Re-Visit the Cut Wires and Repairs for issue that the Butt-Connectors can hide since soldering wires is the only Best Practice to follow for power sensitive circuits that emanate from the Ignition-Starter Circuit.

(2) Even without any signs of Rodent Predation...There are Under-Hood Nesting materials present in those photos showing that either that Mice and Rats dragged that stuff up and around the Fuse Block, elevated above predators. Un-Bolting the Upper Fuse Block from the Lower Harness connectors and looking things over around there with a Bright Flashlight can often show locations of Chewed Through Wiring not visible in plain sight.

I will remove the butt connectors tomorrow and opt for soldering the wires and then wrapping them in electrical tape. I don't think this is the problem because with the first yellow wire (the incorrect one), it makes a click noise in the dash when the wires are touched, and it did this when using the butt connectors. And the second yellow wire, when connected with the butts, activated the security light. (Which wasn't on until they were reconnected.)

Not to disregard your idea, but just to give room for ideas on anything other than this as being the problem.

Also every hooded vehicle in my property has the pine needles in these edges, (they are located directly under the small gap between the hood and the body of the truck when closed.)

I will take a look underneath the fuse block tomorrow as well to make sure everything is clean and in order.

 

[mrrsm]

Just in case you had two yellow looking wires cut at the same time...take closer look at the reconnected ones in those images... their opposite ends look slightly dissimilar in color, so it never hurts to double check such things. We have all made this mistake (if it even has occurred in this instance) from time to time.

 

[BlueDazing]

I'm not sure if this can help narrow anything down but, TJBaker57 says that his truck would stay running when he would used the mechanic switch, whereas mine shuts off.

Maybe if we can find a way to keep it running, I won't need the key to work.

Then again, the issue stopping the key from working is probably the same thing stopping the truck from running longer than a second. So fixing one will fix both.

 

[BlueDazing]

Just in case you had two yellow looking wires cut at the same time...take closer look at the reconnected ones in those images... their opposite ends look slightly dissimilar in color, so it never hurts to double check such things. We have all made this mistake (if it even has occurred in this instance) from time to time.

I connected the first wire before snipping the second. But just incase my memory is failing me, I will take a closer look tomorrow when I go to solder them.

And I will make sure not to make that exact mistake during my soldering endeavors.

 

[TJBaker57]

I'm not sure if this can help narrow anything down but, @TJBaker57 says that his truck would stay running when he would used the mechanic switch, whereas mine shuts off.

Maybe if we can find a way to keep it running, I won't need the key to work

During the whole startup event from the moment the key is turned away from OFF the Body Control Module (BCM) and the Powertrain (engine&transmission) Control Module (PCM) are communicating with each other. The BCM announces on the network what position the key is in and watches for the right signals from the Passlock sensor (anti-theft). At the same time the PCM is announcing things on the network also. The PCM and BCM talk back and forth working out if it's cool to crank, start and run the engine.

One of the final events is the PCM has to send a message with a good "fuel continue password". The BCM has to approve this "password" or it sends a message back to the PCM telling the PCM to kill the power to the fuel pump. This would happen within a second or two after the engine starts. I am suspicious if this is what is at least sometimes what is happening here.

I know this fuel continue password needs to be relearned anytime a PCM or BCM or Passlock sensor is replaced but I do not know if there are any other situations or events that could cause this to have to be done.

 

[Mooseman]

Just to get it out of the way, you should try the security relearn EXACTLY as described below:

1. Attempt to start the truck by turning the key to the Start/Run position. Try to crank the vehicle.
2. Observe that the vehicle fails to start and the security light is illuminated.
3. Release key to the ON/RUN position (not the ACC position or OFF)
4. Allow the vehicle to sit with key in the ON/RUN position for no less than 11 minutes. Security light will turn off after this.
5. When the light goes off, turn key to OFF position and allow the vehicle to remain in the OFF position for 10 seconds.
6. Repeat #1-#5 for four cycles or until vehicle starts.

 

[BlueDazing]

During the whole startup event from the moment the key is turned away from OFF the Body Control Module (BCM) and the Powertrain (engine&transmission) Control Module (PCM) are communicating with each other. The BCM announces on the network what position the key is in and watches for the right signals from the Passlock sensor (anti-theft). At the same time the PCM is announcing things on the network also. The PCM and BCM talk back and forth working out if it's cool to crank, start and run the engine.

One of the final events is the PCM has to send a message with a good "fuel continue password". The BCM has to approve this "password" or it sends a message back to the PCM telling the PCM to kill the power to the fuel pump. This would happen within a second or two after the engine starts. I am suspicious if this is what is at least sometimes what is happening here.

I know this fuel continue password needs to be relearned anytime a PCM or BCM or Passlock sensor is replaced but I do not know if there are any other situations or events that could cause this to have to be done.

Is the fuel continue password relearn the same as the security relearn?

 

[BlueDazing]

...and that leads us back to your Quite Excellent Photos... "Occam's Razor" bears out that "The Simplest Explanation of any problem is almost 99.99% Correct..." The Two locations that draw attention are:

(1) Re-Visit the Cut Wires and Repairs for issue that the Butt-Connectors can hide since soldering wires is the only Best Practice to follow for power sensitive circuits that emanate from the Ignition-Starter Circuit.

(2) Even without any signs of Rodent Predation...There are Under-Hood Nesting materials present in those photos showing that either Mice or Rats dragged that stuff up and around the Fuse Block, elevated above predators. Un-Bolting the Upper Fuse Block from the Lower Harness connectors and looking things over around there with a Bright Flashlight can often show locations of Chewed Through Wiring not visible in plain sight.

Alright, so I soldered the wires, which gave me a chance to do another security relearn, as when I disconnected them I tried to start the truck just for the heck of it. (Which obviously didn't work.)

When the wires were soldered, the security light was then flashing.

The security relearn only lasted one cycle. I left it for 10 minutes, the light turned off and then I turned the key to off for 10 seconds. I turned the key back to run, but the security light did not come back on.

I've also taken a look under the fuse block and there were no signs of rodent damage/infestation, everything was clean.

 

[mrrsm]

Good... Two less things to worry about... You have probably already done this.. But jik-not...

(1) Pull these Fuses and Relays and examine their *tines* for signs of corrosion and Backlight to more closely examine the illustrated-highlighted Fuses. It is rare... but occasionally, Fuses can get Fractured and STILL work long enough for the current flow to Heat Up the Tiny Melt Element... and separate the electrical connection. THESE are all PCM, BCM or Fuel Delivery related Fuses and Relay. If you have Brand New Fuses on hand...Why not just replace these?

One less thing to worry about:

 

[BlueDazing]

During the whole startup event from the moment the key is turned away from OFF the Body Control Module (BCM) and the Powertrain (engine&transmission) Control Module (PCM) are communicating with each other. The BCM announces on the network what position the key is in and watches for the right signals from the Passlock sensor (anti-theft). At the same time the PCM is announcing things on the network also. The PCM and BCM talk back and forth working out if it's cool to crank, start and run the engine.

One of the final events is the PCM has to send a message with a good "fuel continue password". The BCM has to approve this "password" or it sends a message back to the PCM telling the PCM to kill the power to the fuel pump. This would happen within a second or two after the engine starts. I am suspicious if this is what is at least sometimes what is happening here.

I know this fuel continue password needs to be relearned anytime a PCM or BCM or Passlock sensor is replaced but I do not know if there are any other situations or events that could cause this to have to be done.

So based on your order of operations, I attempted a workaround that unfortunately failed, but I now have new knowledge to share.

I'm not sure if this helps but, I turned the key from off, to run, and then when the dash lights settled, I turned it to crank. I released it from crank and went to the back seat to disconnect the 2 plugs coming out of the BCM.

I then attempted to start the truck with the mechanic switch. It died after 1 second, as usual, but the security light did not come on this time.

 

[BlueDazing]

Good... Two less things to worry about... You have probably already done this.. But jik-not...

(1) Pull these Fuses and Relays and examine their *tines* for signs of corrosion and Backlight the illustrated-highlighted Fuses. It is rare... but occasionally, Fuses can get Fractured and STILL work long enough for the current flow to Heat Up the Tiny Melt Element... and separate the electrical connection. THESE are all PCM, BCM or Fuel Delivery related Fuses and Relay. If you have Brand New Fuses on hand...Why not just replace these?

One less thing to worry about:
View attachment 107475
View attachment 107476

I did find corrosion on some of the fuses, and scraped them with a wire brush. Still no luck sadly.

 

[mrrsm]

Okay... Just to have these Diagrams in common for anyone in need of a Ready Reference... Here are the ones showing the Starting Circuit, The Ignition Circuit and The Class 2 Network... Just in case we are missing something here...

 

[budwich]

quote: "One of the final events is the PCM has to send a message with a good "fuel continue password". The BCM has to approve this "password" or it sends a message back to the PCM telling the PCM to kill the power to the fuel pump. This would happen within a second or two after the engine starts. I am suspicious if this is what is at least sometimes what is happening here."

I think this is the most likely issue... and I think you are headed towards bad comms between the pcm and bcm... maybe. Iirc, from past tjbaker "learning threads", the data path between the pcm and bcm comes in two ways, one thru the normal data path used by all units and the other via a direct path between the two. Maybe an issue there. One other area is battery lines on the ignition switch as it is moved thru its positions. Those have to be at specific levels at each position to convey switch position. Those should be checked.

 

[BlueDazing]

quote: "One of the final events is the PCM has to send a message with a good "fuel continue password". The BCM has to approve this "password" or it sends a message back to the PCM telling the PCM to kill the power to the fuel pump. This would happen within a second or two after the engine starts. I am suspicious if this is what is at least sometimes what is happening here."

I think this is the most likely issue... and I think you are headed towards bad comms between the pcm and bcm... maybe. Iirc, from past tjbaker "learning threads", the data path between the pcm and bcm comes in two ways, one thru the normal data path used by all units and the other via a direct path between the two. Maybe an issue there. One other area is battery lines on the ignition switch as it is moved thru its positions. Those have to be at specific levels at each position to convey switch position. Those should be checked.

How can I check the direct path between the PCM and BCM?

And how can I check the battery lines on the ignition switch?

 

[BlueDazing]

quote: "One of the final events is the PCM has to send a message with a good "fuel continue password". The BCM has to approve this "password" or it sends a message back to the PCM telling the PCM to kill the power to the fuel pump. This would happen within a second or two after the engine starts. I am suspicious if this is what is at least sometimes what is happening here."

I think this is the most likely issue... and I think you are headed towards bad comms between the pcm and bcm... maybe. Iirc, from past tjbaker "learning threads", the data path between the pcm and bcm comes in two ways, one thru the normal data path used by all units and the other via a direct path between the two. Maybe an issue there. One other area is battery lines on the ignition switch as it is moved thru its positions. Those have to be at specific levels at each position to convey switch position. Those should be checked.

I'm thinking maybe the battery lines idea could be something to look into, because if the PCM and BCM direct path was the problem, then I assume the key would work, and would start the engine, but then the engine would fail after a second of running. So unless that direct path between the two can also contribute to the key not starting the engine, it might not be the problem.

What we know, is that the key is not activating the starter relay, problem one. But providing alternate start methods still does not bear good results.

 

[BlueDazing]

I apologize for making so many individual replies, but ideas just keep coming to me.

So we have two issues here. The key is not activating the starter relay, and even if the starter relay is activated, the truck will not stay running.

It's either we have two separate issues, or one. If we have two separate issues causing the key to not work, and the truck to not stay running, then that complicates things.

But if the problem is one, and both the key not working, and truck not continuing to run, are from the same issue, then that surely narrows it down some.

What area of the truck is responsible for BOTH, the keys recognition inside of the relay, AND the truck being shut off after a second of running?

Instead of looking at areas that only deal with one of those at a time, maybe looking at areas that deal with both, will help determine the root cause of the problem.

 

[mrrsm]

And as per @budwich 's observation regarding the Dual Class 2 Feeds to the BCM... This fragment show where to probe those two connectors for continuity of the BCM to PCM communications if any such interruptions need investigation:



If checking ANYTHING on the Class 2 Network becomes an issue... Please follow Will Robinson's Superb Training Video on How to pull down the Class 2 Network in any Trailblazer or Envoy ...and watch as he then brings back each module... one at a time. Ultimately...You will come to appreciate learning everything he reveals in THIS Video.

Now... Don't be discouraged in the first few minutes of viewing. Even though Will employs a whole range of Expensive Scan Tool Kits... in time, he PROVES that these Diagnostics can still be done with Basic Tools and a common sense approach via Good Observations (AND a Fully Charged Battery):

 

[budwich]

I am going by the "history" of the truck... supposedly, a "jumper switch" was installed and worked at one time (true? the current owner specifically knows this / tried it previously?). An equivalent operation now works to start but not to run.... this happened with nothing changed other than time (except maybe a few wire cuts... )
Another thing that bothers me is tjbaker's statement that the system knows when the start relay isn't there.... That can only happen via the energizing coil which gets the ground in some form therein.

Tjbaker... how does the pcm know that start relay isn't there?

Bluedazing... pull the start relay and do an impedance check on that pin that goes towards the pcm for the ground. I guess my question would be is, what happens if the pcm is actually grounding that circuit BUT for whatever reason its not making it out to a relay.... is that how the PCM knows its not there... ie. no current flow?

 

[BlueDazing]

And as per @budwich 's observation regarding the Dual Class 2 Feeds to the BCM... This fragment show where to probe those two connectors for continuity of the BCM to PCM communications if any such interruptions need investigation:

View attachment 107484

If checking ANYTHING on the Class 2 Network becomes an issue... Please follow Will Robinson's Superb Training Video on How to pull down the Class 2 Network in any Trailblazer or Envoy ...and watch as he then brings back each module... one at a time. Ultimately...You will come to appreciate learning everything he reveals in THIS Video.

Now... Don't be discouraged in the first few minutes of viewing. Even though Will employs a whole range of Expensive Scan Tool Kits... in time, he PROVES that these Diagnostics can still be done with Basic Tools and a common sense approach via Good Observations (AND a Fully Charged Battery):

Alright so, I'm still not sure exactly what I am looking for. I have easy access to the splice pack in the front, the BCM in the back has 2 plugs coming out of it, and I see a lot more than 2 light green wires.

Is there a splice pack in the back that I am looking for?

 

[mrrsm]

Re: @budwich 's Observations... Check out THIS area of the overall Starting System Wiring Schematic...down in the Lower RH Corner:

 

[mrrsm]

Because trying this "Splice Pack Pull Down" is relatively easy to perform....by pulling the Metal Comb fron the Under Dash Splice Pack...it would take the BCM OFF LINE from any Class 2 Communication. THEN...Try and Start the Vehicle and see if it does... Remembering that with ALL of the Class 2 Modules being OFF LINE.... You will NOT have a NormaI IPC View (Instrument Panel Cluster). Trying this technique out might confirm that the Class 2 Network Comms through the BCM to the PCM IS involved IF the Vehicle Starts Right Up.

 

[BlueDazing]

I am going by the "history" of the truck... supposedly, a "jumper switch" was installed and worked at one time (true? the current owner specifically knows this / tried it previously?). An equivalent operation now works to start but not to run.... this happened with nothing changed other than time (except maybe a few wire cuts... )
Another thing that bothers me is tjbaker's statement that the system knows when the start relay isn't there.... That can only happen via the energizing coil which gets the ground in some form therein.

Tjbaker... how does the pcm know that start relay isn't there?

Bluedazing... pull the start relay and do an impedance check on that pin that goes towards the pcm for the ground. I guess my question would be is, what happens if the pcm is actually grounding that circuit BUT for whatever reason its not making it out to a relay.... is that how the PCM knows its not there... ie. no current flow?

The previous owner of the truck must have installed the jumper switch, I found it there just the other day and was not sure what it was there for. I tried it out, and it started the truck. That's how I learned what it was. I assume it worked for the previous owner of the truck, and it seems to be working for me now as well. As in, it starts the truck, which is its only job. The truck won't stay running though due to another issue (likely the same issue preventing the key from working.)

I am getting 0 resistance in the pin you asked me to test. I tried with the key in crank, and with the key off.

 

[BlueDazing]

Because trying this "Splice Pack Pull Down" is relatively easy to perform....by pulling the Metal Comb fron the Under Dash Splice Pack...it would take the BCM OFF LINE from any Class 2 Communication. THEN...Try and Start the Vehicle and see if it does... Remembering that with ALL of the Class 2 Modules being OFF LINE.... You will NOT have a NormaI IPC View (Instrument Cluster Panel). Trying this technique out might confirm that the Class 2 Network Comms through the BCM to the PCM IS involved IF the Vehicle Starts Right Up.

After taking the comb out of the splice pack, the truck still does not start with the key, and when starting it using the jumper switch, it does not stay running.

 

[mrrsm]

If all of the Security Criteria are being met and the SUV Briefly Starts and Quits... Because the Fuel Pump is controlled by Variable PWM Signals (Pulse Width Modulation) to the Fuel Pump Relay coming from the PCM... Perhaps the PCM Fuel Pump Circuit PWM MOSFET Driver is failing.

Also... AFTER plugging the Splice Pack Comb back together...Consider that since the 5 Volt Reference Voltage is being supplied by the PCM can also get "Short Circuited" by a Failed Electro-Viscous Fan... I'd also be tempted to Un-Plug IT at the Front Left Side of the Radiator and then try once again to start the vehicle. I know... I realize this is all OBPITA. But since these actions are non-destructive and do not involve using any Exotic Tools and Tactics...

What The Hell...Right?

 

[mrrsm]

We have not talked about the Ground Side of all these Circuits yet... But consider that The Fuel Pump Relay...The Left Turn Signal ...AND... The Left Headlight ALL share a Common Ground at G-107 on the Driver's Side of the Lower Engine Block...Checking all those Engine Block Grounds, Cleaning them down to Bare Metal AND then applying a small amount of Dielectric Grease before re-attaching them all... Also Would NOT Hurt.

Refer to THESE Images for Ground Locations and other data:

Electrical Ground locations

While troubleshooting a bad ground I came across some scans of the service manual regarding electrical ground locations for our platform posted on another site. This includes both short and long wheel base, as well as both 4.2L and 5.3L. Credit goes to Wex...

gmtnation.com

 

[BlueDazing]

If all of the Security Criteria are being met and the SUV Briefly Starts and Quits... Because the Fuel Pump is controlled by Variable PWM Signals (Pulse Width Modulation) to the Fuel Pump Relay coming from the PCM... Perhaps the PCM Fuel Pump Circuit PWM MOSFET Driver is failing.

Also... AFTER plugging the Splice Pack Comb back together...Consider that since the 5 Volt Reference Voltage is being supplied by the PCM can also get "Short Circuited" by a Failed Electro-Viscous Fan... I'd also be tempted to Un-Plug IT at the Front Left Side of the Radiator and then try once again to start the vehicle. I know... I realize this is all OBPITA. But since these actions are non-destructive and do not involve using any Exotic Tools and Tactics...

What The Hell...Right?

I tried starting the truck with the key after un-plugging that fan, it would not start, and when starting the truck with the jumper switch, it still shuts off.

 

[mrrsm]

Just saw THIS Dude struggling with a similar problem... and HE came up with an Odd "Dealer Recommended" solution:

 

[BlueDazing]

The security light does not come on when attempting to start the truck with the key. It does come on after starting the truck with the jumper switch.

Given that the security light does come on after starting the truck with the jumper switch, is it possible that the Passlock system is being bypassed in this scenario?

Edit: As in, with the key in run/even after turning it to start before attempting to use the jumper switch, the security system is not responding properly to the key, and is actually being bypassed, which causes the security system to activate when starting from the jumper switch. (Because it thinks there is no key/the wrong key/being bypassed entirely to not even check for the key.)

If TJBaker's truck would stay running after using the jumper switch, the security system was obviously happy with his key, so it had no reason to activate and shut down the truck when he used the jumper switch

 

[budwich]

The previous owner of the truck must have installed the jumper switch, I found it there just the other day and was not sure what it was there for. I tried it out, and it started the truck. That's how I learned what it was. I assume it worked for the previous owner of the truck, and it seems to be working for me now as well. As in, it starts the truck, which is its only job. The truck won't stay running though due to another issue (likely the same issue preventing the key from working.)

I am getting 0 resistance in the pin you asked me to test. I tried with the key in crank, and with the key off.

sorry, just to confirm, you are testing the pin in the fuse block where the relay was for the connection going towards the pcm.... and using a ground reference for your meter? "0" does not sound right... I suspect you are on the voltage scale and not resistance.

 

[BlueDazing]

sorry, just to confirm, you are testing the pin in the fuse block where the relay was for the connection going towards the pcm.... and using a ground reference for your meter? "0" does not sound right... I suspect you are on the voltage scale and not resistance.

If you follow the pin layout in the video mrrsm sent me at the start of this thread, where the 2 top pins get 12v, and the two bottom are meant for ground, I was testing the bottom left pinhole.

I had the meter set to 20k on (i forgot what it was), basically the same setting that i used to read the 1.20ko of resistence that i get in fuse #17.

And i actually used fuse #17 to test if i was properly reading resistance, and came up with the same 1.20ko value that i had gotten last night. But then for the bottom left pinhole for the relay, i was reading 0. I made sure i was getting proper contact too.

 

[budwich]

If you follow the pin layout in the video mrrsm sent me at the start of this thread, where the 2 top pins get 12v, and the two bottom are meant for ground, I was testing the bottom left pinhole.

I had the meter set to 20k on (i forgot what it was), basically the same setting that i used to read the 1.20ko of resistence that i get in fuse #17.

And i actually used fuse #17 to test if i was properly reading resistance, and came up with the same 1.20ko value that i had gotten last night. But then for the bottom left pinhole for the relay, i was reading 0. I made sure i was getting proper contact too.

ok... then check the other pin that you think gets a ground.

 

[BlueDazing]

ok... then check the other pin that you think gets a ground.

The resistance value for that pin jumps all around, I sort of got it stable at around 8-9ko but it kept climbing before dropping to 0, I likely wasn't getting a good connection. But it was reading resistance.

 

[budwich]

I am somewhat confused with the "0". what does your meter read when you set it to resistance and any range and have no leads plugged in to it.... Ie. no measurements being taken.

one of the two plug pins of interest should have 0 all the time. The other should have some reading maybe depending on the underlying pcm circuit (might have some solid state device with high impedance until it is "powered / commanded"). You would likely see some wandering measurement BUT I don't think it should ever read "0" without being in "start" mode.

 

[BlueDazing]

I am somewhat confused with the "0". what does your meter read when you set it to resistance and any range and have no leads plugged in to it.... Ie. no measurements being taken.

one of the two plug pins of interest should have 0 all the time. The other should have some reading maybe depending on the underlying pcm circuit (might have some solid state device with high impedance until it is "powered / commanded"). You would likely see some wandering measurement BUT I don't think it should ever read "0" without being in "start" mode.

The meter itself when set to any measurement, shows 0 until given any type of input/output for the device to read.

I had it set to 20k in impedance mode(or whatever the mode is called) and it would show 0.0k (I think it was "k", I would have to go back up and check, but you get the idea.)

So the 2 top pins, always read 12v with the meter in voltage mode, whereas the two bottom pins in impedance mode show their own respective scores.

The left pin shows "0", as in there was no resistance measured.

The right pin definitely had a reading, it just wasn't stable.

So I am getting "0" on one pin, and a reading on the other as you said I should be getting

The pin that gets "0", gets it in start, and in run/off, so if it is not supposed to be reading "0" unless in start, then maybe that is an area to questioned?

 

[TJBaker57]

Is the fuel continue password relearn the same as the security relearn?

Yes it is.

 

[budwich]

The meter itself when set to any measurement, shows 0 until given any type of input/output for the device to read.

I had it set to 20k in impedance mode(or whatever the mode is called) and it would show 0.0k (I think it was "k", I would have to go back up and check, but you get the idea.)

So the 2 top pins, always read 12v with the meter in voltage mode, whereas the two bottom pins in impedance mode show their own respective scores.

The left pin shows "0", as in there was no resistance measured.

The right pin definitely had a reading, it just wasn't stable.

So I am getting "0" on one pin, and a reading on the other as you said I should be getting

The pin that gets "0", gets it in start, and in run/off, so if it is not supposed to be reading "0" unless in start, then maybe that is an area to questioned?

hmmm .... are you sure it isn't "OL" as in "overload" which in resistance measurement is "infinity" (ie. high resistance).

I think we need to ensure what / how the meter works. What model is it?

 

[TJBaker57]

The security relearn only lasted one cycle. I left it for 10 minutes, the light turned off and then I turned the key to off for 10 seconds. I turned the key back to run, but the security light did not come back on.

So I am wondering if you are doing the relearn correctly and not writing your messages here right,,, or are you still NOT doing the relearn correctly.

You say here the "turned the key back to run". Do you not understand that you are supposed to turn the key to START?? Turning to RUN will NOT make the security light come on and stay on. The directions tell you to try to START the engine, not to just turn the key to RUN.

These procedures will never work unless the steps are followed EXACTLY as the directions say.

 

[Mooseman]

Just saw THIS Dude struggling with a similar problem... and HE came up with an Odd "Dealer Recommended" solution:

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