DTCs: C1278 and C1282
Thread Starter
Cruising
Joined: Apr 2021
Posts: 10
Likes: 2
From: Atlanta, GA
DTCs: C1278 and C1282
I recently bought a 2004 convertible with 36,000 miles and picked up a C1282 code (Yaw Rate Sensor Bias Circuit Malfunction) and "Service Active Handling" message while driving straight and level at 78mph. Front right brake kicked in, hard, but I held a straight line, which turned off the automated systems. Subsequently, I had a failed ignition relay and horn relay, which I'm sure had nothing to do with the braking issue, but may have had something to do with a new, but lousy battery installed by the previous owner. I replaced that battery with an Optima red top. During the ignition relay escapade, I also picked up a C1278 (TCS Temporarily Inhibited By PCM)--that code did not come up the first few times that C1282 came up and first showed itself during the "Reduced Engine Power" episode with several other engine-related faults that all cleared with the new ignition relay. I cleared the C1278 and C1282, but they came back, this time at low speed with no obvious braking.
I've looked at the wiring and grounds; no corrosion, Yaw Rate Sensor is secure on it's moorings. I don't have a Tech II, but have looked at the manual and see a failing EBCM as a possible cause for both codes.
Does anyone have any ideas on this? Thanks!
I've looked at the wiring and grounds; no corrosion, Yaw Rate Sensor is secure on it's moorings. I don't have a Tech II, but have looked at the manual and see a failing EBCM as a possible cause for both codes.
Does anyone have any ideas on this? Thanks!
Drifting
Joined: Mar 2018
Posts: 1,365
Likes: 414
From: New Jersey
Sounds like you yaw rate sensor ckt has an issue. Without a tech2 I don't know if there's much you can do except check the wiring with a digital volt ohmmeter and if it's not too expensive replace the yaw sensor with a known good one. A tech2 or clone would allow you to read the other sensors i.e. the steering wheel position sensor, thats related to this failure and see if their data is reasonable.
Thread Starter
Cruising
Joined: Apr 2021
Posts: 10
Likes: 2
From: Atlanta, GA
Problem solved!
I took the car in to the mechanic to try to figure out the C1282 problem. He said that the best bet was for me to send the EBCM off to be checked out/rebuilt, so he removed it from the car. I called one of the shops that do a good job with the rebuild and talked with them...the rebuild would not fix the problem. I put the EBCM back on, figuring that I'd drive the car until the problem occurred again and then take it in to another shop I know that is tech savvy. As I was connecting the wiring harness to the EBCM, i realized that the harness clamp on the EBCM was missing. I pushed the harness on and secured the basic harness clip and then used zip ties on the EBCM and harness posts to cinch the harness to the EBCM as tightly as possible. I've driven over 100 miles and have had no recurrence of the issue. I know that bad connections were one of the possible causes of the fault, and it appears that the missing wiring harness clamp allowed the harness to wiggle just a little loose and cause that intermittent problem. It is still going to take me a minute to trust the brake system after the few times that the system jammed one of the brakes on while I was going down the road. At any rate, so far, so good!
Last edited by mojo117; Jun 1, 2021 at 03:45 PM.
Thread Starter
Cruising
Joined: Apr 2021
Posts: 10
Likes: 2
From: Atlanta, GA
So...my hope that the problem was the EBCM harness not being locked down with the clamp was dashed. The "Service Active Handling System" fault came back on with C1282 and C1283. I just disabled the system by turning off the TCS for a while, but finally got a chance to take it in to a local shop with a good reputation for dealing with this. We found an OEM yaw rate sensor and steering wheel position sensor and they replaced both parts. The car is is fault-free and drives like a champ.
Last edited by mojo117; Dec 7, 2021 at 07:03 PM.
Race Director
Joined: Oct 2004
Posts: 12,864
Likes: 4,668
So...my hope that the problem was the EBCM harness not being locked down with the clamp was dashed. The "Service Active Handling System" fault came back on with C1282 and C1283. I just disabled the system by turning off the TCS for a while, but finally got a chance to take it in to a local shop with a good reputation for dealing with this. We found an OEM yaw rate sensor and steering wheel position sensor and they replaced both parts. The car is is fault-free and drives like a champ.
Thread Starter
Cruising
Joined: Apr 2021
Posts: 10
Likes: 2
From: Atlanta, GA
The shop couldn't find one..."it's on nation-wide back order." (AKA, "out of stock"!) I googled around and found an OEM one at 1A Auto. I think it was their last one. I just checked Rock Auto and they have Standard Motor Products steering wheel position sensors for $96 and GM OEM ones for $101.
https://www.rockauto.com/en/moreinfo...PT%2Fxz0ahx%2B
https://www.rockauto.com/en/moreinfo...PT%2Fxz0ahx%2B
https://www.rockauto.com/en/moreinfo...PT%2Fxz0ahx%2B
https://www.rockauto.com/en/moreinfo...PT%2Fxz0ahx%2B
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