Wiring/PCM question..

Reply Subscribe

Thread Tools

Search this Thread

Jun 18, 2008 | 06:09 PM

flyinZ

Thread Starter

TECH Addict

iTrader: (15)

Joined: Jun 2002

Posts: 2,642

Likes: 0

From: IL

Wiring/PCM question..

I've got a problem with my 94'z...I have an SES light and both of my fans are on...idles fine(since I replaced the plugs).I tried to scan the car half a dozen times, and it kept saying "no response from pcm.).I sent it back to my tuner, he checked everything out and it was fine. He took my pcm and put it in another car, adjusted the tune for "his" injectors, and the his car fired right up. NO codes, NO fans, nothing!! Our final conclusion is, that it has to be in the wiring of the car. The only recent wiring that was done to the car is when we did an A4-M6 swap. There was some wiring done in the pcm, but Im not sure what.(since I didnt do it.)

Does anybody have any suggestions? Thought about checking out the trans. harness, even unplugging it to see if that helps any..Can anybody help me???

Jun 19, 2008 | 02:31 AM

Dadic 78

Launching!

Joined: Apr 2008

Posts: 201

Likes: 0

Did the car run after the tranny swap?

When you hook up your scanner are you sure it's operating properly? Proper COM port chosen? If you've got the wrong COM port selected, you'll get the "no response from PCM" response.

Jun 19, 2008 | 02:09 PM

flyinZ

Thread Starter

TECH Addict

iTrader: (15)

Joined: Jun 2002

Posts: 2,642

Likes: 0

From: IL

Yes, ran fine. It was tuned after that, by the shop that did the swap. No codes or anything. Yes, proper COM port selected.

Jun 19, 2008 | 07:44 PM

flyinZ

Thread Starter

TECH Addict

iTrader: (15)

Joined: Jun 2002

Posts: 2,642

Likes: 0

From: IL

Where would I find the transmission harness? What color wires, would the reverse back-up lights and the skip shift be?

Jun 23, 2008 | 06:38 PM

flyinZ

Thread Starter

TECH Addict

iTrader: (15)

Joined: Jun 2002

Posts: 2,642

Likes: 0

From: IL

Little update for this topic....After two different laptops, two different cables, and a Snap-on scanner, I still can't access the pcm. The only time we can access it, is when its in a completely different car.

Does that make sense?

Jun 23, 2008 | 11:17 PM

i420tom

9 Second Club

iTrader: (11)

Joined: Mar 2007

Posts: 351

Likes: 6

From: chicago burbs

I remember that certain codes make the fans turn on, i just cant remember what it is. Also my cable has switch on it to make the fuel pump turn on one way and the fans turn on the other way, when the switch is in the middle i can connect to my car. I would look at which codes cause the fan to come on and start there.

Jun 24, 2008 | 09:41 PM

flyinZ

Thread Starter

TECH Addict

iTrader: (15)

Joined: Jun 2002

Posts: 2,642

Likes: 0

From: IL

Would anybody know, the diagnostic pinout, then I could see whether Im getting power there, test the serial data pin, and my grounds..Im starting to hate this car...