: i'm ready to give up on 98 malibu
i got a 98 malibu that i can't get running. first off, it's a ................98 malibu LS, 3100 v6. the car would start then die. i found this forum and done some reading. took car to shop, checked all fuses, feul pump, codes, everything was good. found out the auto theft crap was the problem. got the car started and cut the yellow wire and put in a toggle. auto theft light stayed on but the car started and ran great. lasted for about 2 months and then started doing the same crap again. starts and dies. tried flipping the toggle back to normal and going through the turn key to on and wait 10-20 min over and over again. i can't get this car to stay running no matter what i do. i did notice that my daylight running lights do not work anymore when the key is on. i also used a volt meter and checked the 3 wires that connect to the key switch. with the key on, the yellow wire only had 1.3 volts and the white wire only had 3.4 volts.
i would really appreciate any and all help as i'm ready to take this car to the scrap yard.
10-03-2010, 09:47 PM
It sounds like a battery problem. Check the IPC/BFC ACC fuse in the left instrument panel fuse block. The voltage across the junction with the key ON should be 12V or higher. Then, check the Air Conditioning Compressor/Body Function Control Module fuse in the engine compartment fuse block. The voltage across that junction with the key ON should be 12V or higher as well. If they are low, check the voltage across the battery itself.
10-03-2010, 10:02 PM
Ah, I found the wiring diagrams:
Body Computer (http://cid-54465800aad91b49.office.live.com/self.aspx/pub/va103965.pdf)
10-04-2010, 05:57 PM
password for the diagrams?
10-04-2010, 06:48 PM
Oh, just click on Download. You'd need to sign in/up only if you want to leave a comment.
thanks, i will give it a try tuesday after work. would a bad battery really make the car start and die.
10-04-2010, 08:37 PM
Yep, especially if it's drawing more amperage than the alternator can generate, or if the alternator has crapped out and isn't charging it at all. Below a certain threshold the PCM just won't function.
10-04-2010, 09:10 PM
The reference voltage has to be 5V or higher (any excess gets bled off by a Zener diode, I think).
BTW, the way I used to check the voltage level at the fuse block was to put the positive probe into the holes on top of the fuse and measure the voltage against the known ground. Come to think of it, I don't even know those mini ATM fuses have holes on top.:(
10-05-2010, 05:02 AM
They do, but you have to have what seems like a straight pin for a probe tip!
When I worked in a Ford dealership service department, the PCM would not function below about 10.5 volts (or something near that) even if you could get the starter to crank. I wonder if something similar is happening here?
10-05-2010, 10:41 AM
Ugh, the wonders of miniaturization.:( It does sounds like an insufficient voltage is coming from the battery. The starter will crank as long as the solenoid clicks in the full battery voltage/current through the thick battery cable. That other, thin cable from the battery terminal may be the cause of the voltage drop.
ok, i check the voltage where specified and it was 11.78v. i put in a new battery...problem still the same. car starts runs for 1 sec and dies. when i turn the key to on, it takes about 10-15 secs for my auto theft light to come on. once the auto theft light comes on, it stays on forever, never goes off and never flashes. is there a way to test the BCM. i got a feeling thats my problem.
10-05-2010, 07:28 PM
If I understand this right, with the key from OFF to ON (no attempt at start), the THEFT SYSTEM flashes and then become solidly lit. That means a Passlock system problem. The 10-minute learn procedure only works if indicator flashes. For a solid indicator, there should be diagnostic code(s) stored in the PCM and/or BCM (BFC). Unless you have access to a sophisticated scan tool, I'm afraid there's no good way to tell if it were the BCM or the ignition switch itself.
i thought it was the switch when all this first happened so i bought a brand new switch and towed the car to a chevy dealer so they could program the new switch. the guy told me that he couldn't get his passlock pc to communicate with the car and he couldn't program the switch. he said it had to be something else. i just hate to guess that it's the BCM and spend that kind of money and it not fix the car.
10-05-2010, 10:10 PM
Sorry to hear that. The replacement ignition switch just needs the 10-minute learn. I'd have let them diagnose it properly once it was known that the BCM wouldn't respond to the scan tool. I suggest taking it to the dealership or a reputable shop. If it turns out to be the BCM, the new one will need to be properly programmed and mated to the PCM.
the car has a BCM and a PCM. is there a way to check the PCM or can i try a used PCM to see if thats the problem. if so, where is the pcm located. thanks for the help and time you put helping.
10-06-2010, 06:46 PM
The PCM is on the left side of the dash, left of the OBD connector. The PCM is doing what it's supposed to do in this case, i.e., cutting the engine off. It's the BCM that's obviously failing to give the all-clear. It's my best opinion that you've done all you can and thus it's time to take it in to a shop.
one last question. can i get a used ignition switch, bcm and pcm all from the same year vehicle and do a complete switch. i know i can't mix and match used parts but what about a complete switch of all 3 parts.
10-06-2010, 09:52 PM
That appears to be common thinking. I suppose it could work if the set is from a identically equipped vehicle and the problem isn't in the wiring. If you'd like to try, be sure to unlock the radio first, is all I can add.
12-18-2010, 01:27 AM
reading this makes me feel like a dealer tech again lol