What Does P0228 Mean?
This code indicates the throttle/pedal position sensor/switch C circuit is outputting a voltage higher than the ECM's maximum expected threshold, typically above 4.8V. This high input suggests an internal sensor fault, open ground circuit, or short to voltage in the wiring harness.
Common Causes
35%
Failed pedal or throttle position sensor C with internal fault causing output to pin near supply voltage
25%
Open ground circuit for sensor C causing the signal voltage to float high toward reference voltage
25%
Signal wire shorted to 5V reference or battery voltage in the wiring harness
15%
ECM internal pull-up on the sensor C input circuit
Diagnostic Steps
1
Step 1: Measure sensor C signal voltage at the pedal connector with key on. A reading above 4.8V confirms the high input condition.
2
Step 2: Disconnect the pedal sensor and check signal voltage at the ECM harness side. If voltage drops, the sensor is faulty. If it stays high, there is a wiring issue.
3
Step 3: Verify the ground circuit for sensor C has less than 0.5 ohms resistance from the connector to the ECM ground pin.
4
Step 4: Inspect wiring from the pedal area to the ECM for shorts between the signal wire and reference or battery voltage wires.
5
Step 5: Replace the accelerator pedal assembly and verify sensor C output sweeps correctly through the full pedal travel.
Estimated Repair Cost
$150 - $500
Parts + labor, varies by vehicle and location
This code indicates the throttle/pedal position sensor/switch C circuit is outputting a voltage higher than the ECM's maximum expected threshold, typically above 4.8V. This high input suggests an internal sensor fault, open ground circuit, or short to voltage in the wiring harness.
The most common cause of P0228 (Throttle/Pedal Position Sensor/Switch C Circuit High Input) is: Failed pedal or throttle position sensor C with internal fault causing output to pin near supply voltage
Typical repair costs for P0228 range from $150 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A high sensor C signal may be interpreted as full throttle request, triggering immediate protective fuel cutoff and limp mode. This causes a sudden and significant reduction in power that can be hazardous in traffic.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0228 to identify the root cause.
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Quick Info
Category
Powertrain
System
Electronic Throttle Control System
Difficulty
Type
Generic (SAE)
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