P0221: How to Diagnose & Fix — Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance
6 vehicles · 4 makes · $50-$900 repair
How to diagnose and fix P0221: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Ford Transit Connect · 2014–2021
Owners report sudden reduced power, poor throttle response, and limp-home behavior due to electronic throttle body contamination/wear or throttle actuator control faults. The issue can be intermittent and may clear after a key cycle, then recur, which is a common pattern in NHTSA complaints and owner reports. It often sets throttle/ETC-related DTCs and can be triggered by carbon buildup or failing throttle position sensing.
Common Symptoms
- Reduced engine power message/limp mode
- Poor throttle response or no acceleration
- Stalling or near-stalling at idle
- Intermittent issue resolved by key cycle
- Check engine light on
How to Fix
Confirm DTCs and perform throttle body inspection/cleaning if contamination is present; if faults persist, replace the throttle body assembly and perform the required idle/throttle relearn procedure. Inspect related wiring/connectors and verify PCM updates if applicable.
Sources for this issue (1)
Chevrolet Impala · 2006–2016
Impalas frequently throw a cluster of warnings at once — 'Engine Power Reduced,' 'Service StabiliTrak,' and 'Service Traction Control' — that are usually one underlying drive-by-wire fault rather than three separate failures. The most common root cause is the electronic throttle body actuator (or the dual throttle-position sensors inside it) going out of range; the accelerator pedal position sensors can also disagree. Because the ECM cross-checks these dual sensors, any disagreement forces the car into limp-home mode with drastically reduced power. Carbon buildup on the throttle plate aggravates it, especially in cold weather.
Common Symptoms
- 'Engine Power Reduced' message with limp-home mode
- 'Service StabiliTrak' and 'Service Traction Control' lights together
- Sudden loss of acceleration
- Rough or surging idle, worse in cold weather
- Intermittent recovery after key cycle
How to Fix
Scan for throttle/pedal DTCs before replacing parts. Start by cleaning the throttle body (a frequent cause, cheap fix). If codes/symptoms persist, replace the electronic throttle body assembly (ACDelco 12670981 fits the 2012-2013 3.6L; verify the correct unit for your engine/year). Some 3.6L applications require a relearn/idle relearn after replacement. If the pedal sensors are at fault, replace the accelerator pedal position sensor assembly.
Sources for this issue (1)
Volvo V40 · 2000–2004
The S40/V40 first generation (2000-2004) uses the same problematic ETM as other Volvos of the era. Internal contact wear causes throttle position sensor errors and reduced power mode.
Common Symptoms
- Reduced power mode
- Check engine light
- Stalling
- Rough idle
How to Fix
Confirm ETM failure by scanning for throttle-related DTCs such as ECM-91A7/91B7 or generic P0121, P0221, and by checking live throttle angle signals for dropouts or mismatch between the internal position sensors. On the 2000-2004 V40, the fix is typically replacement of the Magneti Marelli electronic throttle module with an updated/rebuilt unit, followed by throttle adaptation/software initialization with Volvo VIDA or equivalent; inspect and clean the throttle body connector and wiring at the same time. If the car has severe idle instability or stalling, do not rely on cleaning alone, because worn internal contact tracks usually return quickly. Typical repair cost is about $500-$900 using a quality rebuilt ETM and adaptation, or $900-$1,400 with a new OEM unit and dealer programming.
Jeep Wrangler · 2007–2018
Volvo C70 · 1999–2005
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P0221 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0221 mean?
P0221 stands for "Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance." This code means the second throttle or accelerator pedal position sensor (circuit B) is sending a signal that is out of the expected range or does not track properly with the other sensor. Modern drive-by-wire systems use redundant sensors, and the computer compares them for agreement. When sensor B's voltage is implausible or inconsistent, this code sets. It can cause hesitation, surging, reduced power, or a forced limp mode for safety.
What are the most common causes of P0221?
The most common causes of P0221 are: Faulty throttle position sensor (sensor B), Faulty accelerator pedal position sensor, Dirty or worn throttle body, Wiring or connector problems (corrosion, chafing), Poor ground or reference voltage to the sensor, Intermittent open or short in the signal circuit, Faulty PCM/ECM (rare). The specific cause varies by vehicle.
How much does it cost to fix P0221?
Repair costs for P0221 range from $50 to $900, depending on the vehicle and root cause.
Which vehicles are affected by P0221?
Au7o has documented P0221 across 6 vehicle models from 4 manufacturers: Chevrolet, Ford, Jeep, Volvo.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.