2003 crank no start no comm pcm
Thread Starter
Heel & Toe
Joined: Dec 2018
Posts: 23
Likes: 1
From: Brenham Texas
2003 crank no start no comm pcm
just had engine rebuilt started and ran it a few times working on idle tune, at some point tune didnt load and got ses, reduce power, traction, and others in mesages. car ran fine before engine refresh. i have cleaned ignition switch, checked door busses, checked pcm and bcm, cleaned and checked most grounding points, all of which looked fine. disconnected star buss by bcm still wouldnt start. i dont know where or what to try next. any help would be much appreciated!
codes:
pcm no comm
tcs c1277, c1278,u1000
bcm u1255
sdm u1000, u1016, u1040, u1096
ldcm u1096
rdcm u1096
scm no comm aftermarket seat
rfa u1000, u1096
codes:
pcm no comm
tcs c1277, c1278,u1000
bcm u1255
sdm u1000, u1016, u1040, u1096
ldcm u1096
rdcm u1096
scm no comm aftermarket seat
rfa u1000, u1096
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,308
Likes: 3,924
From: Cape Coral, Florida
Since you have a PCM “No Comm” I’d check power and grounds at the PCM..do you have a wiring diagram ??…if your scan tool can communicate with the car you don’t have a data bus issue..there are 2 Star Connectors so if you removed the buss bar or “comb” from the Star Connector with the 8 or 9 wires the car will not start because all the modules on that one are isolated and the BCM and PCM must communicate with each other for the car to start…you would have to jump the 2 terminals on that splice pack !!…you can remove both PCM connectors and check for bent pins or corrosion and then reinstall and then check the power and grounds…you can use a 12 volt test light…the PCM ground (big eye terminal) should be on the same ground as the negative battery terminal and is located above the starter…since the engine was rebuilt I’d check and make sure it is clean and tight !!…if you need the power and ground pin outs on the PCM let us know !!…also a GOOD idea to fill out your profile with model year, mods, tune and location…someone near you may be able to help out.
Thread Starter
Heel & Toe
Joined: Dec 2018
Posts: 23
Likes: 1
From: Brenham Texas
thank you for the response. it turned out to be ignorance.... i was flashing a tune and the battery dropped to low, i was able to do a full write and everything is back to normal. i did however get to check many grounds and learned a bit more on diagnosing the system.
