OBD-II code · Powertrain (generic)
P05C4 Engine Coolant Pressure Sensor Circuit Low
Same as P05C2 with the signal voltage below the plausible range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P05C4?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.4–1.4 h
- Emissions test
- Usually unaffected
- Parts involved
- Engine Coolant Pressure Sensor
Related codes
- P05C1Active Grille Air Shutter Module B Over Temperature
- P05C2Engine Coolant Pressure Sensor Circuit
- P05C3Engine Coolant Pressure Sensor Circuit Range or Performance
- P05C5Engine Coolant Pressure Sensor Circuit High
- P05C6Engine Coolant Pressure Sensor Circuit Intermittent or Erratic
- P05C7Economy Mode Switch Circuit Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.