I have a 2010 Impreza 2.5i premium with the SOHC with 150,300mi and its been going into limp mode periodically for the last two years or more. The car often drives with a slightly laggy throttle and i will sometimes lose power to my accelerator. Usually once i restart the engine it runs fine but sometimes it happens frequently. I have attempted the idle relearn procedure several times and this seems to help for a period of time but the problem always returns. I ran the check engine light and it came back with P2122 Throttle Position Sensor, P2138 Throttle Position Sensor, P0134 No Activity Detected, P0031 Heater Control Circuit Low, and P0171 Too Lean Bank 1. I have replaced the Mass Airflow Sensor, Coolant Temp Sensor, and Throttle Body with a used tnrottle body with 50k miles. I did some research and it seems others have replaced their accelerator pedal and am wondering if this and a possibly a new Oxygen Sensor would help fix the problem, or if theres something else im missing.
P2138 and Recurring Limp Mode
- Thread starter tmgiii
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A replacement Oxygen Sensor is not going to repair P2122 and P2138
P2122
1. Backprobe and check for 5 volt reference from the ECM on the Green/Black wire in terminal B21 with the key on.
2. If there is no 5 volt reference from the ECM on the Green/Black wire in terminal B21, check the Green/Black wire for being shorted to ground in the harness.
3. Backprobe and check the ground for the Yellow/Green wire in terminal B30 at the ECM with the key on - look for 0.05 volts or less.
P2138
1. Use a lab scope to monitor the Accelerator Pedal Position (APP) sensor signal when the problem is happening. If the problem is not happening then the pattern may show good but have a glitch. Terminals 6 and 3 of the APP sensor are the signal wires to the Engine Control Module (ECM).
www.picoauto.com
P2122
1. Backprobe and check for 5 volt reference from the ECM on the Green/Black wire in terminal B21 with the key on.
2. If there is no 5 volt reference from the ECM on the Green/Black wire in terminal B21, check the Green/Black wire for being shorted to ground in the harness.
3. Backprobe and check the ground for the Yellow/Green wire in terminal B30 at the ECM with the key on - look for 0.05 volts or less.
P2138
1. Use a lab scope to monitor the Accelerator Pedal Position (APP) sensor signal when the problem is happening. If the problem is not happening then the pattern may show good but have a glitch. Terminals 6 and 3 of the APP sensor are the signal wires to the Engine Control Module (ECM).
Accelerator pedal position sensor - analog
www.picoauto.com
THROTTLE POSITION SENSOR (TPS)
Our main business is to develop high quality automotive diagnostic equipment, application software and hardware tools for servicing of automotive electronics.
autoditex.com
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they seem to come back immediately, my CEL usually comes on as soon as i start the vehicle.
Ok you have a bad wire or ground or a loose connector. First thing I would do is see if there is a common ground one a wire schematic. That would also tell you a common location where the wires either tie In or run together. A lot of times there are 2 ground straps running from the valve covers to the frame under the car. They are k own for breaking due to getting wet from rain and snow. You can try checking there. When I worked on cars for a living I had a Subaru that had a misfire. Pulled the plugs they were bad so we replaced them with the wire. Took it out for a ride and still had a misfire. Checked the coil and had no response. Replaced the coil. Took it out and still had misfire. Drove me nuts till I seen that they had a common ground wire and it was broken. Put new ground wire on and misfire stopped.
thank you so much, I'm going to try to do some wiring checks on terminals B21 ans B30 and i will update if possible.A replacement Oxygen Sensor is not going to repair P2122 and P2138
P2122
1. Backprobe and check for 5 volt reference from the ECM on the Green/Black wire in terminal B21 with the key on.
2. If there is no 5 volt reference from the ECM on the Green/Black wire in terminal B21, check the Green/Black wire for being shorted to ground in the harness.
3. Backprobe and check the ground for the Yellow/Green wire in terminal B30 at the ECM with the key on - look for 0.05 volts or less.
P2138
1. Use a lab scope to monitor the Accelerator Pedal Position (APP) sensor signal when the problem is happening. If the problem is not happening then the pattern may show good but have a glitch. Terminals 6 and 3 of the APP sensor are the signal wires to the Engine Control Module (ECM).
Accelerator pedal position sensor - analog
THROTTLE POSITION SENSOR (TPS)
Our main business is to develop high quality automotive diagnostic equipment, application software and hardware tools for servicing of automotive electronics.autoditex.com
Thank you so much, I found the wiring diagrams and will try to find the ground straps so i can test the grounds.