Symptoms
Potential symptoms include:
- MIL (Malfunction Indicator Lamp) illumination
- Misfires at idle or highway speed
- Poor idle quality
- May not idle
- May start and stall
Causes
Potential causes of P212A code include:
- Sticking throttle return spring
- Corrosion of MAP or TPS connectors
- Misrouted harness causing chafing
- Faulty TPS
- Faulty PCM
Possible Solutions
If you have access to a scan tool, with KOEO (Key On Engine Off), monitor TPS voltage. With the throttle closed, voltage should be approximately 0.45 volts. It should gradually sweep up to about 4.5 to 5 volts as you press the accelerator. Sometimes only an oscilloscope can capture an intermittent problem in TPS signal voltage. If you notice an issue in TPS sweep voltage, replace the TPS.
NOTE: Some TPS sensors require fine adjustment. If you are not comfortable using a DVOM (Digital Volt Ohm Meter) to adjust the new TPS, then it is best to take the vehicle to a shop. If voltage is not 0.45 volts (+ or – approximately 0.3 volts) with throttle closed or if reading is “stuck,” disconnect the TPS connector. With KOEO, check for 5 volt reference voltage present at connector and good ground. You can check signal circuit continuity by jumpering a fuse wire between TPS connector ground circuit and signal circuit. If TPS reading on scan tool now shows zero, replace TPS. However, if it does not change reading to zero, check for open or short in signal wire and if none found, suspect faulty PCM. If manipulating TPS cable harness causes change at idle, suspect faulty TPS.