An 04 Cadillac with a no crank no start condition and no communication on either the CAN or serial data lines.. How ever if the starter relay is by passed it…
An 04 Cadillac with a no crank no start condition and no communication on either the CAN or serial data lines.. How ever if the starter relay is by passed it…
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What was your solution to the problem? What was the confirmed fix? I
checked all the body grounds G101/G102 and the bus communication purple
wire, i checked pin 36 pin 3 and pin 48 and they all have power, reflashed
vehicle, replaced ecm, replaced the ignition switch and the fuse box panel
and I still have the same issue.
After watching your video I am not sure what part needs replacing, I have
the exact problem you show and if I remove the start relay and jump the
starter it fires every time. When I search for “ECM” I see that the name
seems to be interchangeable with ECU. If I look at pictures online of an
ECM I see a part that matches my part mounted to the side of my fuse/relay
box, but the part they are calling the ECU looks like the part that is
mounted on top of the engine (passenger side) with 2 connectors attached.
Can you suggest which of these 2 parts I should be looking for? I have 2003
CTS. Thanks in advance for any info you can lend to me.
Sounds like a similar issue with the ECM
Hey Mr Greasy Bob did replacing the ecm correct this problem? I have the
exact same problem and have gotten to the same point you did. What solved
this problem. Thank you very much for any information you can give.
Another good video!
Replacing the ECM did solve the problem. Bypassing the starter relay and
engaging the starter would allow the engine to start because it created
enough of a voltage drop on the power supply to the ECM that it would cause
it to “reboot”. Not sure if reboot is the correct word here but I found I
could recreate the condition by temporarily
let me try again.. I used your method and started 05 cts, but I went to
disconnect the pos post, spark spark and more spark, alternator good, but I
don’t have that machine. What else could I check?
Thanks for this vid bob. I have a friend with the same model and her’s is
now doing the same thing. I’ll ask the dealer to replace the ECM as they
could not find any issues when doing the diagnostics. Great info.
Thought my transmission was going out (again), until I ran into similar
starting issues and found your video. This has been a life saver, I was
about to trade the thing in for whatever I could get out of it, but with a
new ECM I’m good as new. Thanks a lot for taking the time to upload this!
I’m curious to know if the new ECM fixed the problem too. My 06 is doing
the same thing. Sometimes it will start everytime i get in then out of no
where it starts acting up again. Jumping the relay cranks the car as you
show and the codes must be cleared before driving or you’re in for a ride
when the transmission starts shifting. I’m getting ready to order a new one
but if it didn’t fix your problem it most likely won’t fix mine. Thanks.
My 05 CTS is doing the same. We went through all the procedures that you
went through. Including re flash with a pass thru, with no luck. I was
leaning towards a ECM, and found this video. You backed up my theory. The
ECM is just so expensive. Thanks for the video though.
Does this apply to all cars with a CAN line?
(continued) shorting the power supply to ground, (not long enough to blow
the fuse). I tried a few used ECMs first but they all eventually started to
have the same problem so I finally installed a new one a while ago and the
vehicle has not had the problem since.
How common is this problem with a bad PCM(or BCM), especially on a GM car?
Usually this is one of the things that GM generally did a nice job on doing
right. However GM did some weird things to the general wiring, such as
running the AC Compressor clutch and part of the BCM off of the same fuse
on the final N-Bodies (Grand Ams and Aleros).
anyone who knows feel free to reply… look at my last comment
Thanks Bob, I have a CTS-V that decided to not start one day, tried
bypassing the starter relay and it worked. hoping I don’t have to buy a new
ECM, though but it seems that will be the cure.