OBD Codes List

Diagnostic reference · P23C5

P23C5

Engine Coolant Bypass Valve C Position Sensor Circuit High

System
Ignition and misfire (P code)
Lamp
Check Engine Light
Category
Powertrain - Ignition

What it means

P23C5 means Engine Coolant Bypass Valve C Position Sensor Circuit High.

Where it lives

For P23C5, the part to look at first is the sensor named here.

Check these first

  • A short to voltage on the bypass valve C position signal wire
  • An open in the bypass valve C position sensor ground
  • A failed bypass valve C position sensor
  • A poor connector pin fit at the sensor C

What to do next

  1. Read bypass valve C position on a scan tool
  2. Test the C position signal wire for a short to voltage
  3. Check the sensor C ground circuit for an open
  4. Wiggle test the C connector pins for poor contact
  5. Replace the bypass valve C position sensor if the wiring tests good
  6. Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.