P0122 Code - Throttle Position Sensor/Switch A Circuit Low Input

Technical Description

Throttle Position Sensor/Switch A Circuit Low Input

What does that mean?

A P0122 code means that the the car's computer has detected that the TPS (throttle position sensor) is reporting too low a voltage. On some vehicles that lower limit is 0.17 - 0.20 volts (V).

Did you adjust it when you installed it? If the signal value is less than .17V then the PCM sets this code. Could be an open or a short to ground in the signal circuit. Or you may have lost the 5Volt reference voltage.

Symptoms

Symptoms may include:

• Rough or low idle
• Stalling
• Surging
• No/little acceleration
• other symptoms may also be present

Causes

A code P0122 may mean that one or more of the following has happened:

• TPS not mounted securely
• TPS circuit short to ground or another wire
• Faulty TPS
• Damaged computer (PCM)

Possible Solutions

Some recommended troubleshooting and repair steps are:

• Carefully check the throttle position sensor (TPS), wiring connector, and wiring for breaks, etc. Repair or replace as necessary
• Check the voltage at the TPS (refer to a service manual for your vehicle for specific information). If the voltage is too low that is indicative of a problem. Replace if necessary.
• If recently replaced the TPS may need to be adjusted. On some vehicles the installation instructions call for the TPS to be properly aligned or adjusted, consult a repair manual for specifics.
• If there are no symptoms at all, the problem may be intermittent and clearing the code may resolve the issue temporarily. If this is the case then you should definitely check the wiring to be sure it's not rubbing on anything, grounding, etc. The code may come back.

Need more help?

If you still need help regarding this trouble code, please post your concern in the forums.

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