rodvet

Can anyone help figure out how to track down the cause for this vette going into Reduced Engine Power, code 1125, when wet?

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?

rodvet

Thanks, I have not checked the starter connection, yet. Battery is new and the connectors are tight.

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.

ZZ06

8VETTE7 suggested looking at the TAC module. Have you done this yet? It sits behind the passenger wheel well.

rodvet

Hi ZZ06, the TAC doesn't look like it is getting wet. I did disconnect the two harness connections and looked at the pins and they look normal, I am not seeing any corrosion.

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.

73Corvette

The larger box is your PCM power control module

rodvet

IT IS FINALLY FIXED!!! Updating this post for the final fix on the Limp Mode issue, Reduced Engine Power 1125 and 1280 and 1281 codes. It was a mouse. See pics. Apparently a mouse had moved in and frayed the wires causing the limp mode to come on whenever I drove in the rain.

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.

rodvet

So far so good, it is June 2016 and had lots of rain here in Texas, problem has not occurred again.

73Corvette

Thanks for the pics and resolving your issue... may be very helpful to another C5 owner someday... glad you got it figured out... dang mice!!!

neutron82

man that was ugly... to anyone with a rodent problem in their car (or anywhere for that matter) you can use dryer sheets to keep them away... there is something in it that they don't like and it's much better than smelling moth *****... I had a mouse getting into my toolbox a few years ago and eating my peanut butter crackers... I took some of the bottom drawers out and put a few sheets back there and the mouse never returned

messenger

I'm having the exact same issues and codes when I get caught driving in rain. Which wires are these, and where should I be looking for them at?

rodvet

I'll try to articulate how to find the "mouse house" area, in a moment. I wanted to share this post, as it has really good info. Even though this was not the actual solution to my problem, it might help solve your problem:

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!