P0122 - Throttle/Pedal Position Sensor/Switch A Circuit Low
P0122 is a generic powertrain diagnostic trouble code indicating Throttle/Pedal Position Sensor/Switch A Circuit Low. It relates to the Fuel & Air Metering system.
DTC Breakdown (SAE J2012)
| System | Powertrain (P) |
| Type | Generic |
| Subsystem | Fuel & Air Metering |
| Fault Index | 22 |
| Standard | SAE J2012 / ISO 15031-6 |
What does diagnostic code P0122 mean?
The powertrain control module logged P0122 due to a Throttle Position Sensor (TPS) low input fault.
Severity Level & Driveability Details
Severity: High
Throttle Position Sensor faults can cause unexpected acceleration or sudden engine stalling, presenting a driveability hazard.
Common Symptoms of P0122
- Engine stumbling, hesitation, or sudden surges.
- Vehicle entering a low-power 'limp home' mode.
- Rough engine idle or engine stalling.
- Check engine light illuminated.
Typical Causes for P0122
- Failed Throttle Position Sensor or throttle body assembly.
- Corroded throttle body wiring connector pins.
- Damaged wiring harness between the sensor and the PCM.
- Loose sensor mounting screws (on older vehicles).
Diagnostic and Troubleshooting Steps
Monitor the Throttle Position percentage on a scan tool to verify it sweeps smoothly from ~10% at idle to ~90% at wide-open throttle without drops or spikes.
Typical Repairs and Fixes
- Replacing the Throttle Position Sensor or the throttle body assembly.
- Cleaning and repairing the wiring harness connector.
- Updating PCM throttle calibration software.
Sensor Location & Parts Involved
The sensor is mounted on the side of the throttle body, connected to the throttle plate shaft.
Clearing Code & Recurrence
Reset the code using a scan tool and perform the throttle body idle relearn.
Emissions & Smog Inspection Impact
Mismatched throttle signals cause incorrect fuel trims, raising exhaust emissions.
Free Check Engine Code Cheat Sheet (PDF)
Got your answer? Keep the top 50 most common diagnostic codes, their meanings, severity levels, and quick fixes handy in your vehicle's glovebox.
Related Diagnostic Codes
Sources & References
This diagnostic guide is compiled and verified against the following authority sources:
- NHTSA Vehicle Complaints
- SAE J2012 diagnostic guidelines
Frequently Asked Questions about P0122
What does the throttle position sensor A circuit low input code P0122 mean?
The powertrain control module logged P0122 due to a Throttle Position Sensor (TPS) low input fault.
Is it safe to drive with the throttle position sensor A circuit low input code P0122 active?
No, a throttle sensor fault represents a stalling or sudden acceleration risk.
How much does it cost to repair a throttle position sensor A circuit low input code P0122 fault?
The sensor itself is $40-$100, while a full electronic throttle body runs $200-$400. Total repair is $150-$600.
What are the common causes of the throttle position sensor A circuit low input code P0122?
Trigger conditions for the throttle position sensor A circuit low input code P0122 include: Failed Throttle Position Sensor or throttle body assembly., Corroded throttle body wiring connector pins., Damaged wiring harness between the sensor and the PCM..
Can I clear the check engine light for throttle position sensor A circuit low input code P0122?
Reset the code using a scan tool and perform the throttle body idle relearn.
Will the throttle position sensor A circuit low input code P0122 cause an inspection failure?
Mismatched throttle signals cause incorrect fuel trims, raising exhaust emissions.