How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Chris (aka- Moose) Your Own Question
Chris (aka- Moose)
Chris (aka- Moose), Cadillac Technician
Category: Cadillac
Satisfied Customers: 48344
Experience:  16 years of experience
2499435
Type Your Cadillac Question Here...
Chris (aka- Moose) is online now
A new question is answered every 9 seconds

I have two codes that pop up when I start the car C1298 and

Customer Question

I have two codes that pop up when I start the car C1298 and U1040. I retrieve these code's with a Snapon Modis scanner. If I clear the codes while the car is running they do not come back until I shut down and restart the car.
Submitted: 10 months ago.
Category: Cadillac
Expert:  Chris (aka- Moose) replied 10 months ago.

Welcome, I'm Chris (aka Moose), my normal schedule online is around lunch and after dinner past midnight.

We need to test the powers and grounds for both the EBCM and PCM while cranking. Normally PCM programming update resolves this but you have done that. If you have a volt meter and understand wire testing we can start checking powers and grounds.

Prior to completing the mandatory rating at the top of your screen. Let me know if I have not yet provided you with ~5 STAR EXCELLENT~service. Reply and let me know in more detail what you need to be pleased with my help.

Thanks Chris

Customer: replied 10 months ago.
powers and ground check ok
Customer: replied 10 months ago.
both on the ecm and ebcm
Expert:  Chris (aka- Moose) replied 10 months ago.

So far you have ruled out all the things that should be to blame, you may need to start redoing these checks and programming. That means the only thing your left with is doing all the pinpoint tests for these codes. Do you have those or need them?

Customer: replied 10 months ago.
i need them
Customer: replied 10 months ago.
did I mention ecm and ebcm were reprogramed
by the way this is a used ebcm and a used ecm and the original was trowing 3 codes for sensors that the dealer were now able to find
Expert:  Chris (aka- Moose) replied 10 months ago.

Being they are used modules that could be your issue. After reviewing the diag steps they only state to reprogram the ECM.

Customer: replied 10 months ago.
it has been reprogram
Expert:  Chris (aka- Moose) replied 10 months ago.

Replacing the ECM with a refurbished one and having the dealer reprogram it would be next step since you have confirmed no weak power or ground supply while cranking is present.

Customer: replied 10 months ago.
r u telling me and it makes sense that I my have weak ground when Im cranking it could be becouse is history codes not current codes which exact ground are you refering to
Expert:  Chris (aka- Moose) replied 10 months ago.

You would need to check all these grounds to see if they need cleaning:

  • G110 and G100 below the thermostat housing on the transaxle.

The powers also have to be checked to see if power is dropped during and after starting.

Expert:  Chris (aka- Moose) replied 10 months ago.

Hello again Chris here,

  • Sorry you were not pleased with my help.
  • What would you like to do regarding your question now.
  • This post is coming up on the 7 day mark where it times out. When a post times out, that means it's no longer on my active list (you reply and I may never know it.)

Thanks Chris