P0227 Code: Throttle/Pedal Position Sensor/Switch C Circuit Low Input

What the P0227 code means

Track C is the third position signal that some manufacturers use (mostly in the accelerator pedal) to confirm the readings from A and B. If its signal is not valid, the computer can no longer verify the pedal and switches to limp mode.

The P0227 code is stored when the computer detects that the signal is below its minimum value (a short to ground or a missing 5 V reference). The sensor works with a 5 V reference, a ground and a signal that should vary between about 0.5 and 4.5 V. The extreme values (close to 0 V or close to 5 V) are reserved for detecting faults: a signal that sits at them does not match any real position or pressure.

Because the pedal is the driver command, the computer is especially strict with its signals: with only one reliable track it cannot rule out unwanted acceleration, so it limits power until the fault goes away and the code is cleared. On many vehicles it also disables cruise control.

Remember that the code tells you where the computer saw the problem, not which part is broken. Look up how the accelerator pedal position sensor is tested if you need the step-by-step procedure.

P0227 code symptoms

• Check engine light on (sometimes the power control light too).
• Limp mode and a slow accelerator response.
• Slow or no response from the accelerator.
• Other related codes for the same sensor.

Likely causes of the P0227 code

1. Signal wire shorted to ground from the harness rubbing on the engine, the body or a metal bracket.
2. 5 V reference open or shorted. It is often shared with other sensors: if several set codes at once, the fault is in the common reference.
3. Damaged sensor with an internal short that pulls the signal to ground.
4. Connector with moisture: water between pins creates a path to ground.

How to diagnose the P0227 code step by step

1. Read the signals on the scan tool and compare them with the other tracks or with the desired pressure.
2. Inspect the connector: look for green, backed-out or oily pins and check that the lock is closed.
3. Check 5 V and ground at the connector with the key on: 4.8 to 5.1 V on the reference and less than 0.1 V of drop on the ground.
4. Measure the signal with the connector plugged in while you move the pedal or the throttle, or accelerate (turbo): it should change smoothly, with no jumps or drops to zero.
5. Do the harness wiggle test with the engine running: move the wiring and watch the reading.
6. Check the continuity of each wire to the computer with the key off (less than 1 ohm).
7. Watch all three pedal tracks on the scan tool while you press it slowly from rest to wide open: they should all change together and without jumps.
8. Check the pedal connector under the dash: it gets wet from shoes and a damp floor mat.

How to fix the P0227 code

• Repair the connector or the wiring.
• Replace the sensor (on electronic throttles, normally the pedal or the whole throttle body).
• Run the throttle relearn if the manufacturer calls for it.
• Clear the codes and verify on the road.

Technical reference data

• 5 V reference, ground and a signal of roughly 0.5 to 4.5 V.
• Tracks A and B: they usually have different slopes or run in opposite directions.
• Approximate values only: check the manufacturer data for your engine.

Brand-specific notes

Track naming varies from one manufacturer to another.

P0227 on GM

The pedal tracks are often identified as D, E and F.

P0227 on Chrysler

The pedal tracks are often identified as D, E and F.

P0227 on Ford

The throttle body and the pedal have two tracks each.

P0227 on Toyota

The throttle body and the pedal have two tracks each.

P0227 on Volkswagen

The throttle body and the pedal have two tracks each.

Frequently asked questions about P0227