Fault code P0221 – a step-by-step guide to diagnosing and fixing it

Error code P0221 is displayed and the check engine light is on - what does this mean?

With DTC P0221, the OBD system detects a malfunction in the accelerator pedal sensor circuit, specifically a range or power error. This trouble code affects the electronic accelerator pedal and the communication between the accelerator pedal and the engine control unit. For some manufacturers, such as BMW or Mercedes, this fault code can also occur as a manufacturer-specific variant.

What causes can this fault code have?

• Defective accelerator pedal sensor (APP sensor)
• Damaged wiring to the accelerator pedal sensor
• Corroded or loose plug connections
• Defective engine control unit (ECU)
• Power supply problems in the accelerator pedal circuit
• Mechanical damage to the gas pedal pedal
• Short circuit in the sensor cable

What symptoms occur in parallel with fault code P0221?

• Irregular idling: The engine runs irregularly or stutters when idling
• Reduced engine power: Noticeable loss of power when accelerating
• Delayed accelerator pedal response: The vehicle reacts sluggishly to accelerator pedal operation
• Emergency running program activated: Engine only runs in emergency mode with limited power
• Starting problems: Difficulty starting the engine
• Jerky driving: Uneven acceleration and vehicle behavior

How can the problem with error code P0221 be rectified?

• The repair requires a systematic approach to identify the exact source of the fault.
• Replace the accelerator pedal sensor completely: Replace the defective APP sensor with a new original part and then carry out a basic adjustment using a diagnostic device
• Repair wiring and plug connections: Check all cables between the accelerator pedal and control unit for damage, repair defective cables and clean corroded contacts with contact spray
• Check and repair the power supply: Measure the supply voltage at the accelerator pedal sensor (should be 5V) and repair defective fuses or relays in the power supply
• Replace engine control unit: If the ECU is defective, replace the control unit with a new or reconditioned unit and have it programmed by a specialist
• Replace the entire accelerator pedal unit: If there is mechanical damage, replace the entire electronic accelerator pedal and recalibrate