engineer

I'm scratching my head on this one. Help me play Sherlock Holmes, or House, or whatever the car equivalent is.

Symptoms and observations

• Engine is severly very low on power and seems to be limiting power intentionally. On a scan tool I can see that it is not commanding the throttle body all the way open despite pedal command to do so.
• This started after some work on the clutch master cylinder. I might have disturbed something. Possibly a wire harness.
• power is NOT limited when depressing the clutch switch. I can unhook the clutch switch to where the car thinks the clutch is always depressed and the car seems to drive fine for a while. Eventually gets suspicious and triggers a p0833 code when it realizes I have been and driving many miles with the clutch "depressed" constantly.
• No DTCs present
• I only have access to a basic scan tool, but all sensors I can read with it seem to be reading withing reason, IAT, TPS, MAP, MAF, pedal position, throttle position, etc.
• problem is intermittent. It came then went for weeks, and is now back again.
• Switch is getting power as expected at the connector. It is powered via the emissions fuse.
• Car is 06 HHR with 2.4L

Questions/Prompts

• WTF does the clutch switch have to do with power limiting. The only documented purpose I can find for this switch is to inhibit cruise control.
• What other systems can nominally limit power? ABS? Knock protection? Do either of these work through throttle or only timing? Are there any IO lines related to them? If I can at least figure out what systems could be related I can start exploring those.
• Is the ECU in these cars coded to other stuff or can I just grab another one and swap it out?

donbrew

Did you remove the fuse box to get to the clutch MC? Check the connectors on the bottom.

Almost everything goes through the computer, The computer itself is rarely faulty. Everything that you think of as a "switch" is actually a "position sensor".

Do you see the "eng pwr reduced" message on the DIC?

There is a RPM limiter when not in gear on automatics, I'm not sure how it works on 5 speeds.

This wire is always a suspect:>