P05C2

What it means

P05C2 is a generic code for a fault in the engine coolant pressure sensor circuit. The engine control unit monitors the sensor's signal voltage and has seen a value outside the expected range, or a signal that does not make sense for the operating conditions. Not every engine has a coolant pressure sensor, so where it is fitted and what it is used for depends on the model and engine.

Symptoms

• Engine warning light on
• Coolant warning or temperature warning on the dashboard
• Reduced engine power or limp mode on some models
• Cooling fan running more than normal
• Coolant loss, or visible leaks around the cooling system
• Other cooling-related fault codes stored alongside

Possible causes

• Damaged, corroded or loose wiring or connector at the coolant pressure sensorlikely
• Faulty coolant pressure sensorlikely
• Real coolant pressure problem, such as low coolant level, air in the system, a weak cap or a blocked circuitpossible
• Coolant leak or seepage into the sensor connector, causing a poor or shorted signalpossible
• Open circuit, short to earth or short to supply in the sensor's reference, signal or earth wirespossible
• Fault in the engine control unit or its sensor supplyrare

How to diagnose

1. Read all stored codes and freeze frame data to see engine temperature, load and conditions when the fault set, and note any other cooling-related codes.
2. Check the coolant level and condition with the engine cold, and look for leaks, residue or signs of overheating.
3. Inspect the sensor, its connector and the wiring for damage, chafing, corrosion, coolant contamination or heat damage.
4. Check the cooling system cap and the system's ability to hold pressure, following the manufacturer's procedure for the model.
5. View live data for the coolant pressure sensor and compare it with the expected value at rest and as the engine warms up.
6. Test the sensor's supply voltage, earth and signal wire against the manufacturer's wiring diagram, and check for continuity and shorts.
7. Check the sensor against the manufacturer's specification, and check for any relevant technical service bulletins for the model.

How to fix

• Repair or replace damaged wiring and clean or replace faulty connectors.
• Replace the coolant pressure sensor if it is out of specification or its signal is faulty.
• Top up and bleed the cooling system, and repair any leaks found.
• Replace a faulty pressure cap or other cooling system component that cannot hold pressure.
• Clear the codes after repair and road test to confirm the fault does not return.

Can I keep driving?

Nearby codes

• P05C1GenericActive Grille Air Shutter Module B Over Temperature
• P05C3GenericEngine Coolant Pressure Sensor Circuit Range/Performance