Is my pcm fried? Please Help

RJW · 05-18-2007, 08:41 PM

I was in the middle of a WRITE ENTIRE with hp tuners when my car's battery died.

I replaced it and then I got all sorts of messages, like reduced power, service traction control and the fuel gauge rad empty.

I did another write entire and restored the original tune.

Now car will not start

It has fuel pressure and the plugs fire, but it seems like the injectors are not firing properly.

Did I cook my pcm?

Car is 03 Z06

JeffC5 · 05-18-2007, 11:19 PM

Maybe this will help. Good luck!
jeff
http://forums.corvetteforum.com/show....php?t=1702975

RJW · 05-19-2007, 12:41 AM

Not much help there

Anyhow....I found out that the pcm's from my 01 and 03 are the same, so i swapped in the 01 pcm and still no go

Only problem was I had to disable the theft deterrent, which then cleared that code.

I can't even get a fart out of the car...motor spins, plugs are firing but NO FUEL...even with 60 PSI in the rail.

I even swapped out some injectors and still no go...

At least it seems as though the pcm is NOT the problem.

What would cause the injectors NOT to fire?

foff667 · 05-19-2007, 01:24 AM

03's use a different computer then 01's. Same connector, different guts...1024kb vs. 512kb.

RJW · 05-19-2007, 03:41 AM

I checked several ecu places, including gmpartsdirect...and they all list the same part number for 01 and 03

Nonetheless, I have been reading the service manuals and about the theft deterrent system. The BCM (body control module) locks out the starter and sends a signal to the pcm to not fire the injectors.

despite no codes, I know that the injectors are not firing at all.

minytrker · 05-19-2007, 01:37 PM

99-02 use the same pcm, its a 512k pcm, 03+ use a 1024k pcm. They look the same but are not. Its easy to tell the difference, just look at the plugs, a 99-02 will say red and blue, 03+ will say blue and green. I seel pcm's all the time, you can not swap between the two.

Quote:

Originally Posted by RJW

I checked several ecu places, including gmpartsdirect...and they all list the same part number for 01 and 03

Nonetheless, I have been reading the service manuals and about the theft deterrent system. The BCM (body control module) locks out the starter and sends a signal to the pcm to not fire the injectors.

despite no codes, I know that the injectors are not firing at all.

RJW · 05-19-2007, 01:39 PM

Odd that on my 03 it says red and blue and that is the color of the connector as well

Bill Curlee · 05-19-2007, 04:20 PM

You can NOT just swap in a BCM or a PCM! The BCM and PCM need to be synced to each other. There is a basic sync and relear procedure:

PCM RELEARN PROCEDURE

You can also force a PCM relearn, pulling the fuses will clear the check engine light...

1) Insert key into ignition and turn to the "ON" position, but, DO NOT START THE ENGINE.
2) Open the engine compartment fuse box cover and remove the two 10 amp fuses from position numbers 16 & 23.
a) According to the manual there are two fuse boxes. Use the engine compartment fuse block for this procedure not the instrument panel fuse block.
b) Engine Compartment Fuse Block (correct one): 16 is Power train Control Module A and 23 is Power train Control Module B.
c) NOTE: Your DIC will now display "check" messages for ABS, etc. Do not worry as this is normal.
3) Turn the ignition key to the "OFF" position.
4) Return to the engine compartment fuse box and re-insert both 10 amp fuses for positions 16 & 23.
***************

BCM/PCM RELEARN PROCEDURE

You will need to conduct the PCM/BCM relearn process. This matches their handshake ID's and allows them to talk to each other.

Do this before you worry about VATS issues:

1. Turn on the key for 11 minutes.
2 Turn off the key for 30 seconds.
3. Repeat 1&2 two more times.
4. Turn on the key for 30 seconds.

The car should start and run with the new BCM. Good luck and report back on your progress.
Shirl
SD Racing Enterprises
Aguila, AZ
Coutersy of MrEracer

This will sync the PCM to the New BCM but all of your RPO options will not be retained. You will need a TECH II to program them into the new BCM.

Bill Curlee

minytrker · 05-19-2007, 05:49 PM

Quote:

Originally Posted by RJW

Odd that on my 03 it says red and blue and that is the color of the connector as well

Im sorry I was wrong, I just went and doubled checked through all my tunes, 03 vettes still have a 512, atleast all the ones I have tuned. I looked at a 03 tune earlier and have messed with several trucks from 03 and they all had the 1024k pcms. So the pcm you have is correct, sorry again, my mistake.

RJW · 05-19-2007, 05:55 PM

I am glad to hear that at least the 01 pcm had a chance...!!!!

My service manuals state that you need a tech 2 to get the bcm and pcm to talk to each other

Similar procedure but with tech 2 and going online to gm...Is that procedure documented anywhere?

Will give it a try, but I now have worse problems

when I hook uo the battery, something is bringing down the voltage and relays under right side dash start clicking away

Battery is at 11.7 volts, but when connecting ground cable, there is NO spark and voltage then reads 3.5v

What could be causing this? shorted starter or solenoid?

I guess that I opened a can of worms and now I'm in for the long haul

Thanks guys...please keep it coming...

Bill Curlee · 05-19-2007, 10:13 PM

From what it sounds like,,,,you have a BATTERY issue. Remove the battery and take it somewhere to have it tested! I bet it is BAD!! That would account for the clicking!!!!

Give that a try.

BC

RJW · 05-20-2007, 12:29 AM

brand new $128 battery from advanced turned out to be bad. Dropped voltage to 3.5v after about a dozen attempts to start the car. That problem solved and guess what ?

with fuel pressure gauge, spark checker and injector pulse checker all hooked up, eventully and for reasons unkown, the PCM decided to fire up the car like there was nothing ever wrong with it.

I hit the key and on one turn it started!! Very strange. but I am extremely releived.

so time to tune it up

thanks everyone for the input.