BCM?

AFISHER30

MEMBER
1998 PONTIAC SUNFIRE
2.2L
4 CYL
AUTOMATIC
200,000 MILES

I have a 1998 Sunfire 2.2 and we have done everything to get the car running. It will run for 1 to 5 seconds and shut off. The anti-theft light stays on and wont go off. We are trying to find out if it is the bcm, but can't find it. I was wondering if it is in the ecm and the ecm works as both parts? We searched for the bcm under the dash (took the whole dash and steering out) looked under the fender (found ecm there). All fuel pressure and everything else is fine. We used a scanner and a code p1621 came up which is long term memory. It went away the second time we used the scanner. Completely at a loss here.

11 Replies

CARADIODOC

MECHANIC
33,729 POSTS

Sounds like it's in theft mode. There is a procedure that might solve this. Connect a small battery charger to the battery. Turn the ignition switch to the "run" position until the anti-theft light turns off, (about ten minutes). Turn the ignition switch off, then right back to the run position. Wait again for ten minutes for the anti-theft light to turn off. Turn the ignition switch off, then do that a third time. When the light turns off this time, crank the engine without first turning the ignition switch off.

The battery charger is needed because leaving the ignition switch on for half an hour may run the battery down too much to crank the engine.

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Sunday, March 20th, 2016 AT 3:18 AM

AFISHER30

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5 POSTS

We have done this twice and the light never goes off. It will start out flashing and after ten minutes it will go solid. When it goes solid we turned the key back and did it twice more for ten minutes each time but the light never went out.

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Sunday, March 20th, 2016 AT 3:34 AM

CARADIODOC

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Rats. The only other thing to look at is if there's broken wires going to the ignition switch.

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Sunday, March 20th, 2016 AT 4:02 AM

AFISHER30

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5 POSTS

Do you think it could be the ecm? I am going to order a ecm tonight and have it flashed to my vin if so

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Sunday, March 20th, 2016 AT 5:22 AM

CARADIODOC

MECHANIC
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Now you're beyond my expertise. The best person to ask is Wrenchtech. I'll try to send him a message. I haven't really read about anyone fixing this problem with a computer. I usually see it solved with the reprogramming steps. In case I can't send a message to Wrenchtech, you should repost this question again so it will appear on the list and he can see it.

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Sunday, March 20th, 2016 AT 5:41 AM

WRENCHTECH

MECHANIC
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Hi guys, This car doesn't really have a body control Module. The security module is incorporated into the dash cluster and the PCM merely gets a yes or no message to leave the injectors on. That P1621 is concerning too. It indicates a fatal failure in the PCM memory. You really need a professional level scan tool here to take a real close look at both the dash cluster and the PCM to see if you still have a problem with the PCM. A key signal failure appears as a flashing security light. A solid light usually indicates a hard problem in other components of the security system, likely the dash cluster. The relearn usually won't help in this situation but will have to be done again if any of the components are replaced.

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Sunday, March 20th, 2016 AT 11:55 AM

AFISHER30