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

P0122 Throttle Position Sensor/Switch A Circuit Low Input

OBD-II Trouble Code Technical Description

Throttle Position Sensor/Switch A Circuit Low Input

What does P0122 mean?

This diagnostic trouble code (DTC) is a generic powertrain code and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Honda, Jeep, Toyota, VW, Chevy, Ford, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.

 

A P0122 code means that the the vehicle's computer has detected that the TPS (throttle position sensor) "A" is reporting too low a voltage. On some vehicles that lower limit is 0.17 - 0.20 volts (V). In simple terms, the throttle position sensor is used to determine what position the throttle is at.

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 5 Volt reference voltage.

For more information on the TPS, see What Is A Throttle Position Sensor?

An example of a TPS throttle position sensor:

Symptoms

Symptoms may include:

Rough or low idle Very high 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

Refer to a vehicle specific repair manual to determine the location of the "A" TPS circuit.

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.

TIP: A visitor to our site offered this tip - a P0122 Code can also occur when the TPS is not ROTATED as it is installed. (The tab inside the sensor MUST be touching the rotating pins in the throttle body. In a 3.8L GM engine, this means inserting it with then connector at 12 o'clock before rotating it to 9 o'clock for the final mounting position.)

Other TPS sensor and circuit related DTCs: P0120, P0121, P0123, P0124

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