1999 Corvette Reduced Engine Power 1125 code
I have noticed it only does it when I drive it in the rain, or sometimes when I wash the car.
Things I have done so far:
1-Grounds cleaned and retightened in three areas.
Two of the areas are the front of the engine compartment on the frame rails, just behind the headlights, cleaned and retightened those. Also disconnect the terminals and cleaned pins and sockets.
Third area is on frame rail next to the battery, cleaned and retightened the pig tails connected there.
2-Pulled passenger wheel well opening to the ECM compartment and disconnected the connectors to inspect for corrosion. They looked fine, didn't do anything, just reconnected them.
What else should I check?
I found two other codes, for a total of three now:
1125
1280
1281
When I clear the codes, only 1125 and 1281 come back on.
Let me also clarify, I am calling the smaller black box the TAC, it has smaller connectors and it sits kind of in front of and bolted to the larger box that I am thinking is the ECM. I disconnected the harnesses to both those boxes to look at the pins and sockets and everything looked Ok, no corrosion.
Last edited by rodvet; May 31, 2015 at 07:34 PM.
Let me also clarify, I am calling the smaller black box the TAC, it has smaller connectors and it sits kind of in front of and bolted to the larger box that I am thinking is the ECM. I disconnected the harnesses to both those boxes to look at the pins and sockets and everything looked Ok, no corrosion.
I have chased this issue for two years now. In Texas we had not had much rain, so I really didn't have this Limp Mode thing happening much until this year. With all the rain this spring, it was happening so often that I finally just put in the shop with Jim Tune in Liberty Hill. Jim was able to track it down. I guess I was not able to see the area he got into. See the pics.
Rody Whitfield C5, mouse house
Rody Whitfield C5, Jim also found corrosion from a previous battery leak
Rody Whitfield C5, These wires being exposed, the wetness of driving in the rain was causing the Reduced Engine Power 1125, 1280 and 1281 codes. Since this was only happening in the rain, made it really hard to track down.
Rody Whitfield C5, This is what it looks like now. Jim Pascal of Jim Tune in Liberty Hill Texas does an amazing job.
Last edited by rodvet; Jul 10, 2015 at 10:46 AM. Reason: pic tags need edit
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I have chased this issue for two years now. In Texas we had not had much rain, so I really didn't have this Limp Mode thing happening much until this year. With all the rain this spring, it was happening so often that I finally just put in the shop with Jim Tune in Liberty Hill. Jim was able to track it down. I guess I was not able to see the area he got into. See the pics.
Rody Whitfield C5, mouse house
Rody Whitfield C5, Jim also found corrosion from a previous battery leak
Rody Whitfield C5, These wires being exposed, the wetness of driving in the rain was causing the Reduced Engine Power 1125, 1280 and 1281 codes. Since this was only happening in the rain, made it really hard to track down.
Rody Whitfield C5, This is what it looks like now. Jim Pascal of Jim Tune in Liberty Hill Texas does an amazing job.
https://www.corvetteforum.com/forums...&pmid=17151217
To get to the "mouse house" area, you have to remove the front wheel (passenger side), then remove the wheel well cover. The ECM and TAC modules are behind the wheel well, under the battery, sandwiched between the fender and the frame. It is right in front of the passenger door hinge. The modules are bolted to a housing that is bolted to the frame. I had looked at the wiring harness that is connected to the ECM, but there wasn't anything wrong with the harness or the wiring in that spot where it connects to the ECM and the TAC. The problem was actually in that same wiring harness, but it was behind the computer housing. See the picture I called "mouse house". That is where the harness had been chewed through...I could not see it because I had been a chicken and not taken the ECM housing out. Jim did that for me. He also found the wiring had battery acid damage and that may have been why the stupid mouse was chewing on it? He fixed that, too. Hopefully this helps locate the issue!
Last edited by rodvet; Sep 6, 2016 at 01:25 PM.










