Question no start after major repairs.. ECM?

[toomanyfbodies]

i've had the ECM in and out a couple times since this and plugs can only go one way. good question though...it very well could be something stupid but it also keeps the interior lights on ???? anyone know where i can find a diagram for the wiring of the ECM.. so i can check its power and ground?

[cocobolo95]

4th gen section has 94 & 96 factory service manual to download. Your 97 will share about 99% of the 96 manual info. Manual will have complete wiring diagrams.

If you gotta have 97 wiring diagrams BBB Industries- Premium Alternators, Starters, Power Steering Products will have most of them for download.

[toomanyfbodies]

the alarm is factory... this car is as stock as they come. dealer serviced, original owners. the interior lights are what makes me think security...

[toomanyfbodies]

ok..was just tinkering on it and it appears the lights are due to wire grounding out on the drivers door pin switch. i also tried hooking the scanner again and got nothing. i'm unable to read the ECM as well as the air bags and the abs. it acts like its not even plugged in. so.... ECM or BCM? any ideas which i should try? and which is controlled my the magic chip in the key?

[GaryDoug]

The PCM and the fuel pump run off the same fuse, the PCM BAT one, which is fuse #3 in the I/P fuse panel. When you "jumped" the fuel pump relay, how did you do that, short two pins together or just connect battery voltage to the prime connector? Connecting to the prime connector bypasses the fuse. Jumping the relay contact may not, depending on which two you used.
I would first check the voltage at the PCM BAT fuse, installed or not. It should be 12vdc at all times.

As for your question about the key, the key contacts go to the BCM, which decides whether it is the right one and then sends a signal to the PCM telling it "ok".

[toomanyfbodies]

i pulled the relay and connected the two wires with a 3inch wire by looking at the diagram on the side of the relay. (30 and 87a) the bcm is getting power as well. so if i get a used bcm it still wont start because of the key resister value?

[GaryDoug]

Did you check the voltage at the PCM BAT fuse?

The BCM has nothing to do with the fact that you can't scan the PCM. If you get a used BCM, you will have a 1 in 15 chance of it matching the key value. But You say you have already done the VATS bypass so that wouldn't matter. Since the Security lamp comes on normally for 5 seconds at ignition on time, the BCM is working at least somewhat. And anyway, the security issue you suspect would not prevent the fuel pump from running, it would only lock out the injectors from operating.

You need to figure out why the PCM isn't working. First check the "cigar accessory" fuse. That supplies power to the DLC connector. Then check the orange wires (C2-15, C2-31) at the PCM connectors. They should have 12v there always. Then check the solid pink wire (C2-30), It should have 12v only when the ignition is on. The grounds are more difficult to find. Check for continuity to engine ground of the black-white wires at C1-2 and C3-32. the tan-white wires at C1-18 and C4-1.
C1 is red, C2 is black, C3 is neutral/gray, C4 is blue.

[toomanyfbodies]

fuses are good....orange wires are hot.....pink wire has no key on power

[GaryDoug]

OK then, now we are getting somewhere. By the way, when I suggest you check the VOLTAGE at a fuse, it does not mean to check the fuse itself. The fuse blocks are convenient places to measure voltages. Now that we see there is correct voltage at the orange wires, it will not be necessary to actually check the VOLTAGE at the PCM BAT fuse.
The pink wire tells the PCM to "wake up", and that is missing. The pink wire goes to the PCM IGN fuse, so you can now measure the voltage (fuse installed) there while you trace this. Do so, and report back what you find. If the voltage is bad (0v with ignition switch ON) at the PCM IGN fuse, the problem is with the ignition switch, or less likely, the wiring to the battery through the fusible link "E" next to the battery. If the voltage is ok (12v with ignition switch ON) at the PCM IGN fuse, the problem is with the wiring to the PCM (or perhaps, less likely, you measured the wrong pink wire the first time). Good luck.

[toomanyfbodies]

ok....i'm an idiot...but a happy relieved one. just went to test the fuses again and all were good. i looked at the cover just to see what i was testing. cigar was good, PCM BAT was good, then i saw PCM IGN 10a. I went to test it and it wasn't even in there. i never found any fuses laying anywhere thru all this but the car did sit with the doors off for a week or so and my 3 and 5 years olds thought that was pretty cool. I dont like to place blame but....i'm going to look thru thier stuff for a pretty lil red fuse!!! long story short... it came right to life. Thank you very much!!!

[GaryDoug]

Haha. I am sure the kids said "I didn't DO IT!!!". And we may never know ;-)