Throttle Position (TP) Sensor 2 Circuit
What it means
This is a Chevrolet (GM) manufacturer-specific code, and the same number can mean something different on other makes. TP sensor 2 is the backup the computer uses to verify sensor 1, and this code means its voltage is out of range or its circuit is open or shorted. The system then limits throttle opening because it has lost its cross-check.
Models covered: Chevrolet (GM) models with electronic throttle control, mainly around 1997–2006.
Symptoms4
- Reduced engine power and weak acceleration.
- Check engine or throttle warning light on.
- The vehicle may drive normally for a while, then the fault returns intermittently.
- Irregular idle at times.
Possible causes5
- Moisture or corrosion in the throttle body connector.
- An open or short in the sensor 2 signal or ground wire.
- A failed sensor 2 built into the throttle body.
- A problem with the reference or ground shared with other sensors.
- A fault in the throttle actuator control (TAC) module or engine computer (rare).
How to diagnose5
- Read the codes and note whether P1120 or P1221 are also stored.
- Watch sensor 2 voltage on a scan tool while slowly opening the pedal and confirm it changes smoothly as the system design expects.
- Inspect the connector and nearby wiring for chafing or heat damage.
- Measure reference, ground and signal for sensor 2 and compare with the manufacturer specification.
- Wiggle the wiring gently while monitoring to catch an intermittent fault.
How to fix5
- Clean the connector and replace corroded terminals.
- Repair the damaged wire, re-insulate it and route it away from heat.
- Replace the throttle body if the built-in sensor is confirmed faulty.
- Perform the throttle relearn if required.
- Clear the codes and confirm they do not return after a test drive.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
Wiring and connectors are the low end of the cost, while a complete electronic throttle body is what pushes it to the high end.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
Why does the throttle need two sensors?
The computer compares both readings all the time. If one fails, it cannot confirm the real throttle opening, so it limits power as a precaution.
The fault comes and goes. Is that normal?
Yes. It is often a connector or wire that reacts to heat or vibration, which is why wiggling the wiring while monitoring is part of the test.
What are the generic equivalents?
Newer models use codes such as P0222 and P0223 for low or high voltage in the second sensor circuit.
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What was wrong? (optional)
This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.
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