P0222
Throttle/Pedal Position Sensor/Switch B Circuit Low
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Code P0222 means the powertrain control module (PCM) has detected that the Throttle/Pedal Position Sensor B circuit voltage is below the minimum expected threshold. In a properly functioning system, TPS B typically reads around 0.5V at idle and increases to about 4.5V at wide-open throttle. This code is set when the signal drops below the minimum voltage, often close to 0V, indicating either a sensor failure or a circuit problem.
When this code is present, the vehicle will almost certainly be in limp mode with severely restricted power. The PCM cannot trust the throttle position information from sensor B, so it defaults to a safe operating mode that limits engine power to prevent potential runaway acceleration. You'll find the vehicle very sluggish and limited to low speeds — typically around 20-30 mph.
Diagnosis involves using a multimeter or scan tool to monitor the TPS B voltage in real time. At idle, you should see approximately 0.5V, rising smoothly to about 4.5V as the throttle is opened. If the voltage stays near 0V, check the connector and wiring first — a disconnected sensor or broken signal wire is the simplest fix. If the wiring checks out, the sensor or throttle body assembly needs replacement. On many vehicles, the accelerator pedal also has a B sensor, so don't overlook it as a possible source. After replacement, perform the required throttle relearn procedure.
Severity
Symptoms
- •Check Engine light is on
- •Vehicle immediately enters limp mode
- •Very limited power and acceleration
- •Engine may idle roughly or stall
- •Throttle pedal feels unresponsive
- •Vehicle may not accelerate past 20-30 mph
Likely Causes
The TPS B sensor has failed in a way that produces an abnormally low voltage reading, indicating the throttle is closed or nearly closed even when it isn't.
A broken signal wire or short to ground in the TPS B circuit causes the PCM to read a low or zero voltage signal.
Corroded, bent, or recessed pins in the TPS connector prevent proper electrical contact, resulting in a low voltage reading at the PCM.
On drive-by-wire systems, the accelerator pedal assembly contains its own position sensors, and a failure in the B sensor here can trigger this code.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Replace the throttle position sensor or throttle body assembly
- Repair broken or shorted wiring in the TPS B circuit
- Clean or replace corroded connector terminals
- Replace the accelerator pedal position sensor assembly
- Perform throttle relearn procedure after repair
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Causes and Fixes P0222 Code: Throttle / Pedal Position Sensor / Switch "B" Circuit Low
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