Code definition P0122
Throttle pedal position sensor (TPS) / switch (TPS) Circuit A low input.
What does code P0122 mean?
P0122 is a generic OBD-II code that indicates that the Engine Control Module (ECM) has noticed that the output voltage of circuit A of the TPS sensor is below the sensor’s expected range.
What causes code P0122?
The A output of the TPS sensor circuit to the ECM has dropped below the specified voltage and is 0.2 V or less.
What are the symptoms of code P0122?
- The ECM turns on the Check Engine light and goes into safe mode, cutting power to the throttle actuator to bring the throttle to an open position of approximately less than 6 degrees.
- The ECM controls fuel injection and timing to control engine speed.
- The vehicle could be driven very slowly with limited throttle response.
- The engine could run at a higher than normal idle speed and not accelerate as well as before the ignition problem occurred.
Note: Symptoms are determined by the manufacturer’s ECM safety strategy for the vehicle during malfunction and may vary by manufacturer and vehicle.
How does a mechanic diagnose a P0122 code?
- Scan incoming document codes and review the frozen frame data to see when the code was set.
- Clears OBD-II error codes and retests the vehicle to see if the code came back.
- Visually inspects all TPS connections and cables for loose or damaged parts.
- Compare the data between TPS A and B circuits on the scanner and, if incorrect, perform TPS troubleshooting tests according to the manufacturer’s recommendations.
- If necessary, replace the TPS, clear the codes, and perform a road test.
The most common errors when diagnosing the P0122 code.
- Failure to perform a visual inspection beforehand
- Failure to scan, document, erase, and retest codes for defects
- Replace TPS sensor without indicating that it is the cause of the problem
- No comparison of TPS sensors A and B in terms of specifications before and after repair or replacement
How serious is the code P0122?
The P0122 code will cause the engine ECM to go into safety mode, causing various driving problems such as lack of acceleration, high idle speed, jerking, limited speed or stalling, depending on the manufacturer’s safety mode strategy.
What repairs can repair the P0122 code?
- Repair or replace TPS connector
- Repair wiring if necessary
- Replace TPS with a new sensor
Additional notes on code P0122
- The P0122 code may be accompanied by other TPS codes, so it may be necessary to follow the manufacturer’s troubleshooting tests for each code received to correct the fault.
- Most P0122 code faults involve a faulty TPS sensor or a loose connector.
- All TPS codes will cause the ECM to go into fault mode; the driving symptoms will be more or less the same.
