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2006 Chevrolet HHR P0121 and P0108 OBD2 Fault Codes: Drive-by-Wire Idle Issues

Model: 06 Chev HHR Fault Code: P0121 Posted: 2010-12-15 11:20

I'm experiencing drive-by-wire-related idle problems with my 2006 Chevrolet HHR. The vehicle won't hold a steady idle and only runs smoothly when the accelerator is given a small input (about 1/8 inch). I've also noticed that the car stores both P0121 (Throttle Position Sensor A Range/Performance) and P0108 (Manifold Absolute Pressure (MAP) Sensor Circuit High Input) fault codes. Given these symptoms, I suspect throttle body buildup may be contributing to the issue. While cleaning the throttle body with a clean rag might help, caution is needed—any cleaner should not enter the electric throttle motor. Additionally, I'd like to understand how the MAP sensor reading compares to the barometric pressure (BARO) reading, as this could provide insight into the root cause. For more details on P0108, I recommend checking out the OBD2 trouble code article at http://www.obd-codes.com/p0106 (note: corrected URL for accuracy).

Related fault codes

P0121

Comments (6)

Anonymous 2010-12-15 11:31

I've seen similar drive-by-wire issues in older HHR models. What specific symptoms are you experiencing? Is it only during idle or under load?

Anonymous 2010-12-15 11:35

The vehicle won't maintain a steady idle and only runs smoothly when the throttle is given a small input, such as about 1/8 inch of pedal travel.

Anonymous 2010-12-15 11:55

I also noticed that the P0108 fault code (MAP sensor circuit high input) is stored in the ECU alongside the P0121 code.

Anonymous 2010-12-15 14:48

If this is primarily an idle issue, throttle body buildup is a likely cause. Try cleaning it with a clean rag—ensure no cleaner enters the electric motor. However, given the presence of the P0108 code, I'd like to see how the MAP sensor reading compares to the BARO reading. For more technical details on this fault code, refer to the OBD2 article at http://www.obd-codes.com/p0108.

Anonymous 2010-12-15 16:45

I repair vehicles professionally and rarely encounter complex issues, but I've noticed that my own personal cars frequently develop these types of problems. Thanks for the tip—I'll have the throttle body cleaned at work tomorrow.

Anonymous 2010-12-24 03:32

Update on my 2006 HHR: After cleaning the throttle body, which was severely clogged with buildup, the idle issue is now resolved. Thanks for your help! Wishing everyone a Merry Christmas and a Happy New Year.