P0222 OBD2 Code Guide
P0222 is a powertrain diagnostic trouble code. Use this hub to understand the plain meaning, the first checks to run, and which vehicle-specific guides may be more useful before replacing parts.
Throttle/Pedal Position Sensor/Switch B Circuit Low Input
Code P0222 signifies that the Powertrain Control Module (PCM) has detected an abnormally low voltage signal from the Throttle Position Sensor (TPS) or Accelerator Pedal Position (APP) Sensor 'B' circuit. This sensor is crucial for monitoring the throttle plate's position or the accelerator pedal's depression, providing vital input for fuel delivery and ignition timing. A low input typically suggests a short to ground within the circuit, an open circuit, a faulty sensor, or a wiring issue causing an insufficient voltage return to the PCM. Modern vehicles often employ multiple TPS/APP sensors (A, B, C, etc.) for redundancy and safety, allowing the PCM to compare signals and detect discrepancies. When P0222 is set, the PCM may enter "limp home" mode, limiting engine power and speed to prevent potential uncontrolled acceleration or stalling.
Code verification standard
P0222 is published with SAE J2012 / ISO 15031-6 code structure plus OBD2 P0222 diagnostic context.
First checks
- - Read all stored and pending codes before clearing anything.
- - Save freeze-frame data so you know speed, load and temperature when the code set.
- - Inspect wiring, connectors, fuses, hoses and obvious leaks tied to the named system.
- - Compare live data against realistic values before buying sensors or modules.
- - Clear the code only after repair and complete a drive cycle to confirm it does not return.
P0222 diagnostic path
- 1Begin with a thorough visual inspection of the throttle body area (for TPS) or accelerator pedal assembly (for APP sensor) and its associated wiring harness. Look for any signs of damage, fraying, corrosion, or loose connections. Pay close attention to the sensor connector itself.
- 2Connect an OBD2 scan tool and monitor the live data stream for the Throttle Position Sensor 'B' (or Accelerator Pedal Position Sensor 'B') voltage. With the ignition on and engine off, slowly depress and release the accelerator pedal. The voltage should smoothly increase and decrease without any sudden drops, spikes, or flat spots. A consistently low voltage (e.g., near 0V) or erratic readings would confirm a circuit or sensor issue. Compare it with Sensor 'A' if available.
- 3Disconnect the TPS/APP Sensor 'B' connector. Using a multimeter, check for proper reference voltage (typically 5V) and ground at the sensor connector pins. Then, check the continuity of the signal wire back to the PCM. A low input code often points to a short to ground on the signal wire or an open circuit in the reference voltage or ground supply.
- 4If the sensor is a potentiometer type, you can test its internal resistance. With the sensor disconnected, measure the resistance between the signal and ground pins while manually moving the throttle plate or pedal. The resistance should change smoothly. An open circuit or erratic readings indicate an internal sensor fault.
Verify before repair
- - Repair or replace damaged wiring or connectors leading to the TPS/APP sensor. This includes addressing frayed wires, corroded terminals, or loose connections.
- - Replace the Throttle Position Sensor (TPS) or Accelerator Pedal Position (APP) Sensor 'B' if circuit integrity (proper reference voltage, ground, and signal wire continuity) is confirmed to be good.
- - Clean the throttle body (for TPS issues) if heavy carbonization is impeding the smooth movement of the throttle plate, although a low input code is typically an electrical fault.
- - Inspect the Powertrain Control Module (PCM) for internal faults, but only after all other possibilities have been thoroughly exhausted, as this is a rare cause.
Vehicle-specific pages to check next
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