P0122 code meaning
Throttle/Pedal Position Sensor/Switch A Circuit Low
Powertrain system Generic code P01xx codes Check engine light
What P0122 means
Sensor A is, in practice, throttle position sensor 1 at the throttle body; the accelerator pedal has its own codes (P2120 onwards). With a cable-operated throttle there is a single potentiometer (about 0.5 V closed to 4.5 V wide open). Electronic throttles have two sensors sharing a 5 V reference and ground, usually running in opposite directions – on GM throttle sensor 1 falls from 3–4 V at idle to below 1 V at full throttle. P0122 means the signal voltage of sensor A is below its lower limit – electrically meant, not 'throttle closed': typically an open or grounded signal wire or a missing 5 V reference. Limits: Ford below 0.25 V (detected within 1 s), Saab/GM 2011 below 0.3 V for 1 s, Saab cable system below 0.2 V for 5 s. GM treats it as a one-trip fault and switches to reduced engine power; Ford lights the MIL and wrench lamp and continues on the remaining sensor or in limp mode.
P0122 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0122
- Check engine light, on electronic throttles also wrench lamp
- Limp mode with reduced power ('Reduced Engine Power') on electronic throttles
- Engine barely responds to the pedal or stalls at idle
- High idle, A/C switched off (cable systems)
Common causes of P0122
- Most likelySignal wire open or shorted to ground
- Most likelyConnector at the throttle body loose or corroded
- Possible5 V reference missing (open, or shorted by another sensor)
- PossibleSensor or throttle body faulty
- Less likelyEngine control module faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Throttle position sensorThrottle bodySensor wiringSensor reference voltage
What each part of P0122 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| 22 | The exact fault in that area. |
What to do next
- Note P0122 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0122
What does P0122 mean?
P0122 means "Throttle/Pedal Position Sensor/Switch A Circuit Low". Sensor A is, in practice, throttle position sensor 1 at the throttle body; the accelerator pedal has its own codes (P2120 onwards). It is a generic code, so it means the same on every make.
Is it safe to drive with P0122?
Drive gently and only to a workshop. With P0122 the car can go into limp mode (reduced power) to protect itself.
Will P0122 fail an emissions test?
Yes, it can. P0122 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0122 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0122 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.