P0228 — Throttle/Pedal Position Sensor/Switch C Circuit High Input

What does P0228 specifically mean?

P0228 means the PCM/ECM detected voltage above the permitted range on the throttle or pedal position sensor/switch C signal circuit.

Can P0228 be caused by wiring instead of a bad sensor?

Yes. An open wire, short to voltage, corroded connector, poor terminal fit, or damaged harness can produce the same high-input condition as a faulty sensor.

Is it safe to keep driving with P0228 stored?

Driving may be possible if throttle response remains normal, but a sudden loss of response or reduced-power mode is possible. Prompt diagnosis is advisable, and the vehicle should not be driven if it stalls or surges.

Does P0228 always mean the throttle body is faulty?

No. P0228 identifies a high input from the throttle or pedal position sensor/switch C circuit and does not by itself prove that the throttle body or sensor is defective.

When your check engine light comes on and a scan tool reports P0228, your engine control module has detected that the throttle or accelerator pedal position sensor circuit is sending a voltage signal that exceeds normal operating limits. Specifically, this code indicates a "Throttle/Pedal Position Sensor/Switch C Circuit High Input" condition, which falls under the powertrain category in the OBD2 system. In plain terms, the control unit is seeing a voltage on this circuit that is far too close to battery voltage — essentially, the sensor is reporting a wide-open throttle position when it shouldn't be.

Your vehicle's throttle system relies on precise voltage signals to determine how far the accelerator pedal is depressed. The pedal position sensor (or throttle position sensor, depending on your vehicle's design) sends a variable voltage back to the ECU, which then commands the throttle body motor to match engine air demand. When this signal circuit experiences a short to power, an open ground, or a component failure that forces the voltage high, the ECU logs P0228 and activates the malfunction indicator lamp. The module stores freeze frame data alongside the code, capturing RPM, engine load, coolant temperature, and vehicle speed at the exact moment the fault occurred — information that becomes invaluable during diagnosis.

The ECU needs to see this out-of-range voltage persist across multiple drive cycles before it permanently stores P0228. This two-trip logic helps prevent false triggers from temporary electrical glitches. Once the code is set, the vehicle typically enters a reduced-power mode designed to get you to a repair facility without risking further damage.

Common Symptoms of P0228

When P0228 is active, you may notice one or more of the following driving conditions:

• The engine stalls as you approach a stop sign or red light, sometimes without warning
• Idle speed feels rough, oscillates, or runs higher than the normal target RPM
• Accelerator response becomes sluggish or unpredictable — the engine doesn't rev when you press the pedal
• The vehicle drops into fail-safe (limp) mode, restricting power output significantly
• The Check Engine light remains illuminated on your dashboard
• In some cases, acceleration may feel sporadic or "jumpy" rather than smooth

What Causes P0228?

P0228 can stem from several different failures within the throttle and intake air control system. Here are the most common culprits, ordered from most to least frequently encountered:

• A short circuit where the signal wire contacts battery positive voltage, forcing the voltage high
• Failure of the throttle position sensor, pedal position sensor, or the combined throttle/pedal switch assembly that pulls the signal line high
• An open or corroded ground circuit for the affected sensor, preventing proper voltage reference
• Accumulated carbon deposits or debris causing the throttle plate to stick or move improperly
• Wiring harness damage, connector pins that are bent, corroded, or loose in the throttle circuit
• Failure of the electronic throttle motor that positions the throttle blade
• Intake air leaks downstream of the mass airflow sensor that disrupt the air-fuel mixture

How to Diagnose P0228

Follow these systematic steps to pinpoint the root cause of P0228 without replacing parts unnecessarily:

1. Connect an OBD2 scanner and confirm P0228 is present in the stored codes. Save the freeze frame data immediately — this snapshot shows engine RPM, load, temperature, and speed at the exact moment the fault triggered.
2. Pull all related trouble codes. Codes pointing to the MAF sensor, other throttle circuits, or the powertrain control module can guide you toward the actual problem. Check for any applicable technical service bulletins (TSBs) for your specific make, model, and model year.
3. Perform a thorough visual inspection of the wiring harness and connectors associated with the throttle and pedal position sensors. Look for damaged insulation, pinched wires, corrosion at the connectors, and verify that all pins are making solid contact.
4. With the suspect sensor disconnected, use a multimeter to check signal voltage at the harness side. If you still read high voltage with the sensor unplugged, the wiring itself has a short to power. If the voltage drops to normal reference range, the sensor assembly is faulty.
5. Remove and inspect the throttle body. Clean carbon buildup from the throttle plate and bore using appropriate throttle body cleaner. Verify the plate moves freely through its full range of travel without binding.
6. Clear the code and perform a test drive that replicates the conditions recorded in the freeze frame data. Monitor live data for throttle position and MAF readings — they should respond smoothly as you operate the accelerator. If P0228 returns, the underlying fault is still present.

How to Fix P0228

Depending on what your diagnosis reveals, you have several repair paths. Always address the simplest and most affordable causes before considering expensive component replacements.

Throttle body replacement: When the throttle position sensor or throttle body motor has failed internally, the entire assembly must be replaced. OEM-equivalent units typically run $250–$700 including parts and labor.

Throttle body cleaning: Carbon buildup on the throttle plate is a common trigger for P0228. Professional cleaning runs $80–$200 and often resolves intermittent or minor faults without requiring part replacement.

MAF or MAP sensor replacement: If the mass airflow or manifold absolute pressure sensor is contaminated or failed, expect to pay $150–$400 for the part and installation.

How Much Does P0228 Repair Cost?

Total repair costs for P0228 vary based on which component is actually at fault. Here is a breakdown of typical expenses at independent repair shops in the United States:

• Throttle body assembly replacement: $250–$700
• Professional throttle body cleaning: $80–$200
• MAF or MAP sensor replacement: $150–$400

For most vehicles, you should budget between $80 and $700 to resolve P0228. The cleaning route is the least expensive and is often the fix when carbon buildup is the issue. Accurate diagnosis before purchasing parts is the single best way to avoid overspending — the most expensive scenario is rarely where you should start.

Can You Drive with P0228?

Proceed with caution. P0228 frequently triggers limp-home mode, which reduces engine power significantly — enough to reach a qualified repair shop, but not advisable for long highway journeys or aggressive driving. The reduced power mode exists to protect your engine and transmission when the throttle system cannot be trusted to operate safely. If your vehicle exhibits stalling, complete loss of throttle response, or unpredictable acceleration, do not continue driving. Call for a tow rather than risk a loss-of-control situation. Once the fault is repaired and the code cleared, normal driving resumes without any lasting effects.

Related OBD2 Codes

• P0200: Injector Circuit Malfunction
• P0201: Injector Circuit Malfunction - Cylinder 1
• P0202: Injector Circuit Malfunction - Cylinder 2
• P0203: Injector Circuit Malfunction - Cylinder 3
• P0204: Injector Circuit Malfunction - Cylinder 4
• P0205: Injector Circuit Malfunction - Cylinder 5