P0220
PowertrainThrottle Position Sensor/Switch (TPS) B Circuit Malfunction
On a drive-by-wire car the ECU watches two separate signals coming from the throttle or pedal position sensor and cross-checks them against each other. P0220 is the 'B' circuit reporting a voltage that's drifted outside the window the ECU expects, so it no longer trusts what that sensor is telling it. For you that usually shows up as the throttle going lazy or the car dropping into limp mode to keep things safe. Most of the time it's the sensor itself or its wiring, not the engine.
ⓘ Information only. This page provides general educational information about fault code P0220. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0220 mean?
P0220 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Throttle Position Sensor/Switch (TPS) B Circuit Malfunction.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine warning light on, sometimes with the throttle feeling fine until you push it
- • Flat, hesitant acceleration, like the engine isn't reading your right foot properly
- • Limp mode kicking in, which on a lot of cars caps you to roughly 20 mph and won't rev past idle much
- • Rough or hunting idle, or the engine cutting out when you come to a stop
- • Hard starting now and then, occasionally a no-start
- • Throttle response that jumps about or surges when you hold a steady pedal
Possible causes
Causes commonly associated with P0220, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Faulty throttle position sensor, often built into the throttle body so the whole unit gets replaced. Common on older VAG group cars and a fair few Fords with electronic throttle bodies
- 2. Damaged or corroded wiring and connectors in the throttle circuit, water and road salt get into the loom and the signal goes haywire
- 3. A loose or partially backed-out connector at the throttle body or pedal, enough to upset the reading without falling off completely
- 4. Carbon caked round the throttle bore upsetting how the flap reads, more of a factor on direct-injection engines
- 5. Failing accelerator pedal position sensor, since the 'B' circuit can live in the pedal assembly on some models
- 6. A misadjusted or out-of-spec throttle sensor that's never been relearned after fitting
- 7. PCM fault, rare, and only worth considering once everything upstream checks out clean
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Pull all the stored codes and the freeze frame data first. If there are pedal codes (P2135) or other TPS codes sitting alongside it, that narrows down which circuit and which part you're chasing
- 2. Get under the bonnet and look hard at the throttle body connector and the loom running to it. Wiggle the plug with the ignition on and watch for the signal flickering. Corroded pins are a classic here
- 3. Watch the sensor voltage live with the key on and engine off. Closed throttle should sit around 0.45V and climb smoothly to near 5V at full pedal. A flat spot or a jump in that sweep points straight at the sensor or its wiring
- 4. Back-probe the connector to confirm you've got a clean 5V reference and a good earth. No reference voltage means you're chasing the wiring side, not the sensor
- 5. Clean the throttle bore and flap if there's carbon build-up, then recheck the voltage sweep. Sometimes that alone settles a borderline reading
- 6. If the wiring, reference, earth and sweep all come back good, then the sensor or throttle body is the likely fault. Only look at the PCM after that lot is ruled out
Common questions about P0220
How quickly do I actually need to sort this? +
Don't sit on it. The car will often go into limp mode, which means you're crawling at about 20 mph and that's no place to be on a motorway slip road. Even when it isn't in limp mode, erratic throttle and the odd stall are a genuine safety worry in traffic. Short hop to a garage is fine, planning a long trip on it is asking for trouble.
Is it the sensor that's gone or just the wiring? +
More cases than people expect come down to wiring, a dodgy connector, or a dirty throttle body rather than a dead sensor. That's why swapping the sensor blind is such a common waste of money on this code. Check the loom and the voltage reference before you buy anything. If the reference and earth are solid but the sweep is rubbish, then you're looking at the sensor or throttle body.
How long is this in the garage for? +
A wiring repair or a throttle clean is usually an hour or so once the fault's been pinned down. Replacing a throttle body or pedal sensor is typically an hour to two hours of labour plus the relearn afterwards. Most of the time on this job goes into diagnosis, not the actual fitting, so don't be surprised if the garage charges a chunk of bench time before they touch a spanner.
Can I get away with a cheap aftermarket sensor or throttle body? +
A decent branded aftermarket throttle body or sensor from a reputable UK motor factor will do the job for a daily driver and saves you a fair bit over dealer prices. Where it bites you is the bargain-bin no-name stuff, which can read slightly off and either won't clear the code or sets it again within weeks. On a lot of cars the throttle body needs an adaptation reset after fitting too, so a cheap part that won't relearn cleanly is a false economy. Stick to a known brand.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →