ECM issues, shut off without warning

JBLOUNT

MEMBER
2006 CHEVROLET TRAILBLAZER
5.3L
V8
2WD
AUTOMATIC
128,000 MILES

The check engine light came on so I put it on my own diagnostics tester, the code for the throttle body came up so I replaced it. I drove the vehicle for about 20 minutes and it shut off on me with no warning. I tried to start it back up and I got nothing. The next day it cranked right up and again ran for about 20 minutes and shut off. I brought it to a Chevrolet dealership for service, they put it in their diagnostic test and it came back the ECM and throttle body. They're telling me the new throttle body caused my ECM to fail. My son in law had the vehicle for about 2 years before I bought it from him, and he had no problems with it.

6 Replies

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

Hi,

Was it a new TB or used? Also, did you recheck for codes after the problem started?

I'm trying to determine how the TB caused the ECM to fail. Also, when it wouldn't start, did the starter engage and the engine fail to start, or did the starter do nothing?

Let me know.

Joe

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Tuesday, May 11th, 2021 AT 8:15 PM

JBLOUNT

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4 POSTS

Hello, the TB is new and yes the starter will engage but the engine won't turn over. Yes after I installed the new TB I checked for codes and it was giving the code for the TB and ECM. That's when I took it to Chevrolet and they told me the new TB caused the ECM to fail.

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Wednesday, May 12th, 2021 AT 8:54 AM

JBLOUNT

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4 POSTS

Also the reduced engine power light came on as well.

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Wednesday, May 12th, 2021 AT 8:55 AM

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

I'm not saying it didn't damage the ECM, but here is what I suggest: Since the TB is new, it should be under warranty. I would return it to where you got it for a replacement. Hopefully, that is the problem and not the ECM.

Also, if you have the specific codes that were found, let me know what they are.

Take care,

Joe

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Wednesday, May 12th, 2021 AT 6:05 PM

JBLOUNT

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4 POSTS

These are the codes it is giving, p0443, p0689, p1682, p2101, and p1516. I know that one of these codes was for the ignition switch but I've already changed that. I included all the codes it is giving because I don't remember which one was the ignition switch.

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Thursday, May 13th, 2021 AT 8:05 AM

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

Hi,

A few of the codes are related to the switch and basically, everything seems to be tied into the powertrain relay. Has it been checked? If not, let's start there.

The relay is in the fuse box under the hood. If you look at the attached pic below, I highlighted the relay. If there is a different relay with the same part number, switch them to see if it makes a difference. If there isn't, here is a link that explains how to test one.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Additionally, I want you to check the fuses indicated in pics 2 and 3 for power when the vehicle stops running. The ECM powers these fuses (via the ignition 1 fuse) when the ignition key is turned on, so I want to know if we are losing a signal from the ECM or if the relay itself is bad.

Here is a link you may find helpful when testing for power at the fuses:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Let me know what you find or if you have other questions.

Take care,

Joe

See pics below.

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