PCM no comm
Thread Starter
Heel & Toe
Joined: Sep 2002
Posts: 21
Likes: 0
From: Hallstead PA
PCM no comm
Started getting all kinds of messages, service engine, active handling, traction control, gauges not working etc. have tried just about everything I can find on the forum. New battery, inspect and cleaned grounds, checked and removed star connectors and just jumpered PCM & BCM, car won’t start and getting PCM no comm as well as comm codes for TCS, BCM, SDM. Any suggestions other than pulling the PCM and send it out for test/reprogram?
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,666
Likes: 4,093
From: Cape Coral, Florida
So I see you removed both star connectors shorting bars AND jumpered the PCM/BCM and it still didn't start ??....MMMM ???...which grounds did you clean ??...G106 near the battery ??...the PCM ground is there (black/white wire)...PCM won't work if you have power there but no ground...I just went through some crazy stuff with my '01 last week (P1518, no start, no comm...blah,blah, blah...low battery voltage on DIC... no fuel pump prime...cycled the key on and off a bunch of times and car started so I will changing ignition switch soon....I also cleaned G106 ground...if you jumpered the PCM and you KNOW the ground is good just check for a 5 volt ref. at the MAF sensor real fast KOEO....the yellow wire !!...also PCM fuse...can't remember the number....feeds the control side of ignition relay 42 ...that I remember...LOL !!!
Last edited by C5 Diag; Oct 9, 2018 at 06:06 PM.
Cruising
Joined: Oct 2018
Posts: 10
Likes: 0
So I see you removed both star connectors shorting bars AND jumpered the PCM/BCM and it still didn't start ??....MMMM ???...which grounds did you clean ??...G106 near the battery ??...the PCM ground is there (black/white wire)...PCM won't work if you have power there but no ground...I just went through some crazy stuff with my '01 last week (P1518, no start, no comm...blah,blah, blah...low battery voltage on DIC... no fuel pump prime...cycled the key on and off a bunch of times and car started so I will changing ignition switch soon....I also cleaned G106 ground...if you jumpered the PCM and you KNOW the ground is good just check for a 5 volt ref. at the MAF sensor real fast KOEO....the yellow wire !!...also PCM fuse...can't remember the number....feeds the control side of ignition relay 42 ...that I remember...LOL !!!
Melting Slicks
Joined: Jul 2006
Posts: 2,332
Likes: 31
From: Silver Spring MD
Mine was the Ignition Switch
Had no start and P1518 code pointing to TAC and no communication to PCM. Checked out wires from TAC to TB motor and position sensor, PCM, and accelerator pedal sensors. Replaced TAC. Car cranked fine but wouldn't start. Replaced Ignition Switch. Car started right up. Let me know if you need a TAC. I have one gathering dust.
Last edited by bighank; Jan 20, 2019 at 08:00 PM.
