P0229 moderate

Throttle/Pedal Position Sensor C/F Voltage Correlation

The P0229 code means the vehicle's onboard diagnostic system has detected: Throttle/Pedal Position Sensor C/F Voltage Correlation. This is a moderate severity code.

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Keep driving?
Short distances only
DIY difficulty
moderate
Estimated cost
$100 - $500 (parts and labor)
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Common Symptoms

  • Check Engine Light on
  • Vehicle enters reduced power mode
  • Throttle response feels inconsistent
  • Multiple TPS-related codes may be stored

Probable Causes (Ranked by Likelihood)

  • One TPS sensor reading differently from its paired sensor Very High
  • Carbon buildup on throttle blade causing sensor disagreement High
  • Damaged wiring on one sensor circuit only Moderate
  • PCM calibration or software fault Low

Step-by-Step Diagnostic Procedure

  1. Read all TPS sensor voltages simultaneously on scan tool. Compare TPS C and F readings across throttle range.

  2. Calculate the expected correlation between sensors. They should have a predictable mathematical relationship.

  3. Clean throttle body and retest. Carbon buildup can cause one sensor to read slightly different.

  4. If cleaning does not resolve, replace the throttle body or accelerator pedal position sensor assembly.

Frequently Asked Questions

What does voltage correlation mean?

The PCM compares voltage readings from multiple throttle sensors. They should agree within a calibrated tolerance. A correlation fault means they disagree beyond that tolerance.

Can this be caused by a single bad sensor?

Yes, if one sensor in a pair is drifting or has a dead spot, it will disagree with its partner sensor, triggering the correlation code.

Do I need to replace both sensors?

Not always. Diagnose which sensor is reading incorrectly by comparing all TPS readings. Replace only the faulty component.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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