1997 GA GT Passlock / PCM / Not Starting Questions [Archive] - GrandAmGT.com Forum


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07-24-2007, 10:09 AM
Hi all,

White 1997 Grand AM GT (6 cyl, 3.1L) owner here. Having multiple problems, looking for some advice. I've scoured Google with "bypass Passlock", "PCM location", various other keywords, but have not had much luck yet with different solutions. Seeing as how this site is dedicated EXCLUSIVELY to my car type, figured there might be more knowledgeable fellas here.

Here's my probs:
1) THEFT SYS light is on constantly, no blinking. Definitely something up with the Passlock (I have Passlock 1). Attempt to start car, and it tries to crank but immediately dies like it's not getting fuel. Symptoms of Passlock issue. I can hear the fuel pump when I turn the key to ON position so I think it's fine.
2) When it actually does start, and I drive it down the road, I usually have to keep my foot on the gas when I come to a complete stop (red light) and use my left foot for brake to keep the RPMs up. If I stop suddenly w/o doing this, usually (not always) the RPMs drop to zero and the car dies. I keep the RPMs up by slightly pressing gas, no kill.
3) The dummy lights on the instrument panel will intermittently come on and off while going down the road, and the gauges (RPM and temperature) will fall from their proper position to their lowest position along w/ lights. Lights on, two gauges drop to zero, lights off, they return to proper position (gas gauge and speedometer not affected).
4) I had the ignition lock cylinder/Passlock sensor replaced last August for these very same problems at a Pontiac dealership ($400-500 *cry*). They said this would fix it. Worked fine for a week, then THEFT SYS light came on. WTF? Car would still crank intermittently, but light stayed on. Eventually after a week or two the THEFT SYS light went off and stayed off, car worked fine from late August '06 to last week.
5) I've recognized that the car will ONLY START if all of the dummy lights EXCEPT the Check Engine, Air Bag (this one has always been on since I got it), and THEFT SYS lights are off. I have reproduced this dozens of times, cranks every time when it's like that. I can usually tell when it's about to be crankable - the IPC lights will sort of come on and off, and the gauges will kinda bounce.

Here's the solutions I've tried:
1) Wait 10 minutes BS. Doesn't work anymore. Light doesn't go off after 10 min. Or after 20, or 30. ONLY Cranks when above #5 conditions met.
2) Turn car on, cut yellow Passlock data wire coming out of ignition on steering wheel. The car will still crank intermittently with the yellow wire cut, but not "every time" like many sources claim. It's as if I didn't cut the wire at all.
3) Tried all 3 of my keys. Only one key will ever get it to do anything, and only occasionally at that. Suggest spraying something in there maybe? Maybe not good contact??
4) Checked PCM fuse in driver side fuse panel, A-OK. Checked PCM fuse in underhood panel, A-OK. Where the hell is the PCM at? I read somewhere that it could be loose connection, but I have no idea where the PCM is or what it looks like.
5) Running an ohmmeter b/w yellow data cable and black cable to get a resistance reading. Read 7.95kW. Put some resistors together to the resistance and installed b/w. Car started intermittently just as if I never did anything. Will it only work with relay? I don't have remote starter.

Any ideas? I'm not all that knowledgable about car electronics/mechanics (more of a computer tech), but am trying to learn. Plus I can't afford another $400-500 fix on a college student budget. I bought a Hayes manual that is for my car and several other GM vehicles but it doesn't say shiat about the security system or where the PCM is.

Sorry for all these words to read, but I figured it'd help to tell everything. Hope someone's patient enough to help! :feedback:

07-28-2007, 02:03 PM
Nobody knows where the PCM is at all...?