P0220 is a generic OBD-II powertrain code that means Throttle/Pedal Position Sensor/Switch "B" Circuit Malfunction. The ECM/PCM has detected an electrical or performance problem in the circuit associated with throttle or accelerator-pedal position sensor "B".
P0220 does not necessarily mean that the throttle body itself is defective. Depending on the vehicle design, the "B" circuit may belong to a throttle position sensor (TPS) or accelerator pedal position (APP) sensor circuit.
Modern electronic throttle systems commonly use redundant position signals so the ECM/PCM can compare multiple sensor channels for safety.
P0220 Code Definition
- Code: P0220
- System: Electronic throttle / accelerator pedal control
- Type: Generic OBD-II Powertrain DTC
- Definition: Throttle/Pedal Position Sensor/Switch B Circuit Malfunction
What Does P0220 Mean?
The ECM/PCM receives throttle-position and/or accelerator-pedal-position information from redundant sensor circuits.
These signals allow the control module to determine how far the accelerator pedal is being pressed and how far the electronic throttle is opening.
When the signal from sensor or circuit "B" is missing, electrically abnormal, implausible, intermittent, or outside the expected operating relationship, the ECM/PCM can store P0220.
The exact identification of Sensor B varies by manufacturer. On one vehicle it may refer to a TPS channel, while on another it may refer to an APP sensor circuit.
P0220 Symptoms
- Check Engine Light.
- Reduced engine power.
- Electronic throttle warning.
- Accelerator pedal becomes unresponsive.
- Limited engine RPM.
- Rough or unstable idle.
- Poor acceleration.
- Engine may enter limp-home mode.
- Throttle may remain at a limited opening.
- Vehicle may have difficulty maintaining speed.
- Possible intermittent hesitation.
Because the throttle system is safety-critical, some vehicles will significantly reduce engine torque when a redundant sensor disagreement is detected.
Common Causes of P0220
- Faulty throttle position sensor.
- Faulty accelerator pedal position sensor.
- Damaged throttle-body connector.
- Damaged accelerator-pedal connector.
- Open sensor signal wire.
- Short to ground.
- Short to voltage.
- Missing 5-volt reference.
- Poor sensor ground.
- Corrosion inside a connector.
- Water intrusion.
- Damaged wiring harness.
- Throttle-body internal fault.
- Accelerator-pedal sensor internal fault.
- Low system voltage.
- ECM/PCM fault.
How to Diagnose P0220
1. Scan for All Related Codes
Do not diagnose P0220 alone if other throttle, accelerator-pedal, or 5-volt-reference codes are present.
Codes such as P0120, P0121, P0122, P0123, P0221, P0222, P0223, P2135, or related manufacturer-specific codes can provide important clues.
2. Check Freeze-Frame Data
Record engine RPM, vehicle speed, throttle position, accelerator-pedal position, engine load, system voltage, and other available parameters before clearing the code.
This can help determine whether P0220 occurred during acceleration, idle, startup, or another operating condition.
3. Inspect the Wiring
Inspect the throttle-body and accelerator-pedal harnesses carefully.
Look for:
- Broken wires.
- Chafing.
- Loose terminals.
- Corrosion.
- Water intrusion.
- Terminals pushed backward inside connectors.
- Previous wiring repairs.
4. Check the 5-Volt Reference
Many throttle and pedal position sensors use a regulated reference voltage supplied by the ECM/PCM.
A typical reference voltage is approximately 5 volts, but the exact specification must be verified for the vehicle.
If the reference voltage is missing, do not immediately replace the throttle body. Another sensor sharing the same 5-volt reference circuit could be shorted and pulling the reference voltage down.
5. Check Sensor Ground
Verify the sensor ground circuit using the manufacturer's test procedure.
A poor ground can cause the signal voltage to become incorrect or unstable and may trigger multiple sensor-related codes.
6. Monitor Throttle/Pedal Position Live Data
Use an advanced scan tool to monitor the redundant position signals while slowly operating the accelerator pedal.
The signals should change smoothly and maintain the expected relationship specified by the manufacturer.
7. Check for Signal Dropouts
Move the accelerator pedal slowly from released to fully depressed while observing the live data.
Sudden jumps, dropouts, flat spots, or implausible values can indicate a sensor or wiring problem.
8. Inspect the Throttle Body
If the P0220 circuit is associated with the throttle position sensor, inspect the electronic throttle body and its connector.
Do not assume that carbon deposits alone are responsible for an electrical circuit code.
9. Check the Fuse Box
Inspect the appropriate ECM/PCM, engine-control, throttle-control, and ignition-related fuses where applicable.
Depending on the vehicle, fuse-box labels can include abbreviations such as:
- ECM
- PCM
- ETC
- EFI
- ENG
- IGN
- ECU
Fuse names and locations are vehicle-specific. Always use the correct fuse-box diagram for the exact vehicle.
P0220 Diagnostic Signal Flow
↓
Position Sensor B
↓
5V Reference + Ground
↓
Position Signal
↓
ECM / PCM
↓
Signal Comparison
↓
Throttle Control / Engine Torque
P0220 Live Data Diagnosis
Advanced scan tools can display several redundant throttle and pedal-position parameters.
Depending on the vehicle, monitor:
- APP Sensor 1.
- APP Sensor 2.
- Throttle Position Sensor 1.
- Throttle Position Sensor 2.
- Accelerator Pedal Position.
- Commanded Throttle Position.
- Actual Throttle Position.
- Engine RPM.
- Engine Load.
- 5-volt reference voltage where available.
- Battery voltage.
- Throttle actuator command.
- Throttle actuator current where available.
The most important diagnostic principle is to compare the redundant signals rather than looking at one percentage value alone.
If one signal changes smoothly while the second signal suddenly drops, jumps, or becomes implausible, investigate the corresponding circuit and sensor.
P0220 Typical Sensor Values
Many conventional throttle-position circuits operate within a voltage range of approximately 0.5–4.5 V, but this is only a general reference.
Some electronic throttle systems use different signal ranges or calibration strategies. The exact values must be confirmed using manufacturer service information.
For a redundant system, the two channels are intentionally different and are not necessarily supposed to produce identical voltages.
Therefore, do not diagnose P0220 simply because two sensor percentages or voltages are different. The manufacturer's correlation specification is more important.
P0220 Oscilloscope Testing
An oscilloscope is one of the best tools for identifying intermittent TPS or APP signal problems.
5V Reference
│
▼
Position Sensor B
│
│ Signal
▼
ECM / PCM
│
▼
Signal Correlation
│
▼
Electronic Throttle Control
During a slow pedal or throttle movement, the signal should generally change smoothly without sudden dropouts, spikes, or intermittent interruptions.
An oscilloscope can reveal faults that may be missed by a scan tool because a brief signal dropout may occur too quickly to appear clearly in recorded Live Data.
Can a Bad Throttle Body Cause P0220?
Yes. If the throttle position sensor is integrated into the throttle body, an internal sensor or circuit fault can cause P0220.
However, wiring, connector, reference voltage, and ground faults must be ruled out before replacing the throttle body.
Can a Bad Accelerator Pedal Cause P0220?
Yes. On vehicles where Sensor B corresponds to the accelerator pedal position circuit, an internal APP sensor failure can trigger P0220.
Can a Bad 5-Volt Reference Cause P0220?
Yes. A shorted sensor or wiring problem on a shared 5-volt reference circuit can affect the throttle or pedal-position sensor and generate P0220.
When several unrelated sensors suddenly report reference-voltage faults, inspect the common 5-volt circuit before replacing individual sensors.
Can a Blown Fuse Cause P0220?
It can, depending on the vehicle's electrical architecture.
A blown ECM, ignition, throttle-control, or engine-control fuse can interrupt power to a sensor or control circuit. However, P0220 is more commonly associated with sensor, wiring, reference, ground, or connector problems.
Is P0220 Serious?
P0220 can be serious because it affects electronic throttle or accelerator-pedal information.
The vehicle may enter a reduced-power or fail-safe mode to prevent unintended acceleration or loss of throttle control.
Can I Drive With P0220?
Driving with P0220 is not recommended if the accelerator response is abnormal, the vehicle is in reduced-power mode, or the throttle warning is active.
If the accelerator pedal becomes unresponsive or engine speed behaves unpredictably, stop operating the vehicle safely and diagnose the fault.
P0220 Repair Cost
- Electrical diagnosis: approximately $75–$200+.
- Wiring or connector repair: approximately $75–$350+.
- Accelerator pedal assembly: approximately $150–$500+.
- Throttle position sensor: approximately $100–$300+ where separately replaceable.
- Electronic throttle body: approximately $250–$900+.
- ECM/PCM diagnosis or repair: approximately $150–$1,500+ depending on the vehicle.
Actual repair costs vary significantly according to vehicle, engine, parts prices, labor rates, and the exact cause.
Common Repair Mistakes
- Replacing the throttle body without testing the wiring.
- Replacing the accelerator pedal without checking the sensor signals.
- Ignoring the 5-volt reference circuit.
- Ignoring sensor ground.
- Assuming Sensor B always means the same component on every vehicle.
- Ignoring other 5-volt-reference DTCs.
- Using a generic voltage specification as an exact factory specification.
- Failing to perform a slow signal sweep.
- Ignoring intermittent wiring faults.
- Replacing the ECM/PCM before proving that the module is faulty.
Related Codes
- P0120 – Throttle/Pedal Position Sensor/Switch A Circuit.
- P0121 – Throttle/Pedal Position Sensor/Switch A Range/Performance.
- P0122 – Throttle/Pedal Position Sensor/Switch A Circuit Low.
- P0123 – Throttle/Pedal Position Sensor/Switch A Circuit High.
- P0221 – Throttle/Pedal Position Sensor/Switch B Range/Performance.
- P0222 – Throttle/Pedal Position Sensor/Switch B Circuit Low.
- P0223 – Throttle/Pedal Position Sensor/Switch B Circuit High.
- P2135 – Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation.
- P2101 – Throttle Actuator Control Motor Circuit Range/Performance.
- P2110 – Throttle Actuator Control System Forced Limited RPM.
FAQ About P0220
What does P0220 mean?
P0220 means Throttle/Pedal Position Sensor/Switch B Circuit Malfunction. The ECM/PCM has detected an electrical or signal problem involving the B position-sensor circuit.
Is P0220 a generic code?
Yes. P0220 is a generic OBD-II powertrain code, but the exact component represented by Sensor B depends on the vehicle manufacturer.
Can P0220 cause limp mode?
Yes. Because throttle and accelerator-pedal signals are safety-critical, many vehicles can enter reduced-power or fail-safe operation.
Can P0220 be caused by wiring?
Yes. Open circuits, shorts, damaged connectors, corrosion, and intermittent wiring faults can all produce P0220.
What voltage should a TPS sensor have?
Many systems use a reference near 5 volts and a signal that operates within a range around 0.5–4.5 volts, but exact values vary. Always use vehicle-specific specifications.
What live data should I check for P0220?
Check APP Sensor 1 and 2, TPS Sensor 1 and 2, commanded versus actual throttle position, accelerator-pedal position, engine RPM, engine load, system voltage, and available 5-volt reference data.
What should I check first for P0220?
Start with all stored codes and freeze-frame data, then inspect the connectors and wiring, verify 5-volt reference and ground, monitor the redundant position signals, and test the circuit with an oscilloscope if the fault is intermittent.
Final Takeaway
P0220 is a generic OBD-II code for Throttle/Pedal Position Sensor/Switch B Circuit Malfunction. It indicates a problem with one of the redundant throttle or accelerator-pedal position circuits.
The correct diagnosis should not begin with automatic throttle-body replacement. A professional approach checks 5-volt reference, sensor ground, wiring, connectors, Live Data correlation, signal sweep, and oscilloscope waveforms before replacing expensive components.
Because the exact meaning of Sensor B and the expected voltage/correlation values vary between vehicles, always confirm the circuit identification and specifications for the specific make, model, engine, and year.