Electrical Headache! please help.. 96 cav

[boomer3]

Since this past fall i've been trying to get my sisters cavalier fixed. It started with a no spark condition. So i replaced the ckp, coils, and the ICM, to no avail, then finally one day i had the brilliant idea of checking the PCM. Long story short, it came out in 2 pieces and was more corroded then you can imagine! Along with that, the plugs were also very corroded. So i spliced in 3 'new' junkyard PCM plugs, along with a pcm. Finally the car starts, but only for 2 seconds before passlock shuts her down. I tried the 10 minute re-learn procedure, and also had the pcm reflashed, but its not recognizing the re flash! Anti-theft still shuts the car down. I'm at a loss now. If anybody can give me some suggestions/help, i would really appreciate it. Should i be testing for continuity/resistance in some wires between the ignition switch/ICM/PCM related to the passlock??

[boomer3]

by the way its the base model, with the 2.2. I believe that was the only motor produced in 96, and all cavaliers had the same ecu for that year as well. Any ideas guys! I'm trying to fix her and have hit a roadblock, not sure where to look now.

[discnik]

Does the vehicle have a Mass Air Flow sensor ?

I had a vehicle that acted like it was the security system shutting it down, turned out to be the MAF.

Just a thought.

[boomer3]

no that is not the problem, it is involved in some wiring with the ecu and passlock system but i dont know how to diagnose it, hopefully somebody here will chime in!

[boomer3]

any help from you electrical gurus?

[J-Ri]

Usually with a passlock problem you have to either replace or bypass the lock cylinder. I reccomend bypassing it simply because of cost, of course you won't have any anti-theft system any more. To bypass it, simply cut the signal and ground wires from the BCM and solder a resistor inline on the BCM side of the wires. There is a range of resistors that will work, if the resistance of your lock cylinder is high, replace it with a low resistor. If it's low, replace with high and replace middle with either end. I have a table of the recognizable resistor values at work, which I will post if I can remember to The reason you should change the resistance as much as possible is that it won't relearn if the value is really close to what's in there now.

[boomer3]

Thanks tons for the help, i may have to just do that then. I feel like i would have to keep fishing alot to find the current problem. but before i bypass, i'll see if i can do a few more tests. By the way, i'm embarrassed to say, but i'm not familiar with the 'bcm', only the pcm, and the icm. I thought the icm and pcm were the only 2 systems in line with the passlock system. Just to confirm also, are the wires you're talking about, 3 wires that come right up to the ignition assembly?

[boomer3]

Hey ,finally the weather is warm enought to try and work on a few of these wires. If anybody could give me a bit more advice with the bypass procedure that would be great. I think i understand how to do it, but any extra clear advice would be appreciated! I'm confused as to where to place the leads to measure resistance, ie ignition side of the cut yellow wire or dash side, along with the ground wire. Also, how am i supposed to measure resistance accurately when i can only actually start the car for about 1 - 2 seconds at most?! I was led to believe that the car needs to be running before the resistance measurements will be what i'm looking for. Thanks for the help!

[rhandwor]

With your electrical problems you need a good wiring diagram.
http://www.alldata.com/ Sells a years subscription for around $29.95.
Your getting some good advise but I've found to many poor wiring splices to be confident this isn't your problem. You need to unplug the connections which were spliced. Use an ohm meter and ohm each wire. If you don't have a good set of crimping pliers or didn't solder them this is very important.

[boomer3]

I infact have just done this, and the splicing seems to be doing a solid job, everything is 'ohming out', and all compenents receiving the correct signal from what i can tell. I would like to try this bypass, but am still unclear as to what to do. I'm still not quite sure which wire to cut, there is a ribbon of wires on top of the column that are surely smaller than 20GA that i thought were the passlock wires, and then another article said it was a 20GA yellow wire not in ribbon with other wires, on the underside of the tumbler. So i'm getting confused to say the least, a quick overview might help.

[J-Ri]

I got your e-mail. In the future, please do not e-mail anyone for help. I'm pretty sure that's in the "User Guidelines", if not, it should be. When I have free time, I'm more than happy to help. When I have free time, I'm usually here. Not a huge deal to me, but it went straight to the "deleted" folder.

There are 3 wires that come out of the lock cylinder. Red, Black, and yellow ( I think, it can vary from model to model, and honestly I don't think I've seen this problem on a Cavalier, so it's possible that the wire colors are different from the W and N bodies that I've done so many of). I usually cut the wires as close to the BCM as I can get, but you'll need a wiring diagram to identify which connector/terminal it is. There's nothing wrong with doing it at the lock cylinder, but I like to eliminate a fault in the wire as the problem. All you do is cut the yellow and black wires and solder the resistor between them. What I like do is cut 2x 3" sections of wire and solder them to the resistor on my workbench because it's so much easier there. Solder the wires on so the open ends are facing the same direction, then put two layers of heat shrink tubing over the resistor leads, that makes it stiffer, so the leads on the resistor won't break. Also, use 1/8 watt resistors (the blue ones), the little brown ones aren't rated high enough for this.
-----------------\
------/\/\/-------| <-- solder the wires on like this


Then, if it's very difficult to solder it in the vehicle, I'll just crimp two heatshrink butt-connectors to the short wires and only crimp the resistor in. I like to solder everything when possible, but depending on the space you have, you may be unable to.

[rhandwor]

Go to http://www.bulldogsecurity.com/ Search vehicle wiring diagrams.
You should find information you need.
You can google passlock 1 or 2 for information. Normally this shuts power to the injectors. Some shuts down the fuel pump.
If you search the forum their is information.

[RahX]

PASSLOCK REPROGRAMMING AUTO LEARN

IMPORTANT: Due to component variability, the vehicle theft deterrent (VTD) system must have the learn procedure performed regardless, if the vehicle starts on the first ignition cycle after a VTD repair.

You must perform a theft relearn procedure if any of the following components have been replaced:

* Passlock Sensor
* Instrument Panel Cluster (IPC)
* Powertrain control module (PCM) The above modules, with the exception for the Passlock Sensor must also be programmed with each module's own vehicle configuration.

AUTO LEARN
Time required, approximately 10 minutes:

1. Insure that the battery is fully charged.
2. Use the scan tool in order to clear the DTCs.
3. Turn the ignition switch from the OFF position to the CRANK position attempting to start the vehicle. The vehicle will start and then stall.
4. Leave the ignition switch in the ON position while observing the security indicator.
5. When the security indicator turns off, which can take up to 10 minutes, turn the ignition switch off. Wait 10 seconds.
6. The BCM and the PCM will learn the new code on the next start attempt.

[manicmechanix]

Originally Posted by RahX

PASSLOCK REPROGRAMMING AUTO LEARN

IMPORTANT: Due to component variability, the vehicle theft deterrent (VTD) system must have the learn procedure performed regardless, if the vehicle starts on the first ignition cycle after a VTD repair.

You must perform a theft relearn procedure if any of the following components have been replaced:

* Passlock Sensor
* Instrument Panel Cluster (IPC)
* Powertrain control module (PCM) The above modules, with the exception for the Passlock Sensor must also be programmed with each module's own vehicle configuration.

AUTO LEARN
Time required, approximately 10 minutes:

1. Insure that the battery is fully charged.
2. Use the scan tool in order to clear the DTCs.
3. Turn the ignition switch from the OFF position to the CRANK position attempting to start the vehicle. The vehicle will start and then stall.
4. Leave the ignition switch in the ON position while observing the security indicator.
5. When the security indicator turns off, which can take up to 10 minutes, turn the ignition switch off. Wait 10 seconds.
6. The BCM and the PCM will learn the new code on the next start attempt.

I think this is the solution to your problem. I think when you switched the PCMs the relearn and/or reflash wasn't done properly.

[boomer3]

Thanks for the help guys, ill get back to you within a week or so.. As for the reprogramming, it was tried numerous times, using the original eprom chip, and another eprom chip, with a snap-on scan tool, i really feel that the likelyhood of that being done wrong is low. But dont quote me:P.