OBD-II trouble code
P0222: Throttle/Pedal Position Sensor/Switch 'B' Circuit Low
The second throttle or accelerator pedal position sensor is sending a signal voltage that is too low — typically near zero. The check engine light is on and the vehicle usually drops into a reduced-power 'limp' mode.
Quick facts
- System
- Powertrain
- Category
- Throttle / Idle
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $600
- DIY difficulty
- Intermediate DIY
What does P0222 mean?
Drive-by-wire vehicles use redundant position sensors at the accelerator pedal and throttle body, each reporting a voltage that rises and falls with pedal or throttle angle. The 'B' circuit is one of those redundant signals. Under normal operation its voltage stays within a defined window — for example roughly 0.5 to 4.5 volts across the full range of travel.
P0222 sets when the powertrain control module (PCM) sees the 'B' signal voltage drop below the minimum threshold, often to near zero. Where P0221 is a 'range/performance' fault (the signal exists but its value looks wrong), P0222 is specifically a low-voltage fault — usually caused by a short to ground, an open in the signal or reference wire, a lost 5-volt reference, or a failed sensor stuck at the bottom of its range.
Because the PCM cannot trust throttle demand when a redundant sensor reads implausibly low, it almost always enters a fail-safe or 'limp' mode: throttle response is limited, RPM is capped, and cruise control is disabled. The vehicle remains driveable but noticeably down on power until the circuit fault is found and repaired.
Common causes
- Short to ground in the 'B' signal circuit
- Open (break) in the signal, reference, or ground wire
- Corroded or disconnected connector at the pedal or throttle body
- Failed accelerator pedal position (APP) sensor stuck low
- Failed throttle position sensor inside the throttle body
- Lost or low 5-volt reference from the PCM
- Water intrusion or corrosion in the harness
Symptoms
- Check engine light is on
- Reduced engine power / limp mode
- Poor or delayed throttle response
- Rough or unstable idle
- Cruise control disabled
- Stalling in some cases
Diagnostic steps
- 1.Scan for companion codes. P0222 with P0221 or P0223 helps confirm which sensor circuit is involved; throttle 'A' codes point at a shared pedal or throttle-body issue.
- 2.Inspect the pedal and throttle-body connectors for corrosion, bent or backed-out pins, and moisture; reseat and re-test.
- 3.With the key on, back-probe the 'B' signal wire for voltage. A reading pinned near zero points to a short to ground or a lost reference.
- 4.Check for the 5-volt reference and a good ground at the sensor connector. Missing reference voltage usually means a wiring fault or PCM-side problem, not the sensor.
- 5.With the sensor unplugged, check the signal wire for a short to ground and continuity back to the PCM; repair any damaged wiring.
- 6.If wiring, reference, and ground all check out, replace the affected pedal assembly or throttle body and perform the required throttle relearn.
Repair cost
$100 – $600
Diagnosis runs $75-$150. Wiring and connector repairs can be inexpensive when the fault is a short or corroded pin. An accelerator pedal position sensor is typically $150-$350 installed, and a throttle body $250-$600 installed. A throttle relearn is often required afterward.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with accelerator pedal position sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.