P05C4

Symptoms

• Check Engine Light Is On
• The scanner shows zero or abnormally low coolant pressure readings
• Possible engine emergency mode
• Cooling system warning on display
• At real low pressure - signs of a coolant leak

Causes

• Short circuit of the sensor signal wire to ground
• Break in the power wire (+5V) of the pressure sensor
• Complete failure of the coolant pressure sensor
• Real pressure drop in the cooling system (leakage, pump failure)
• Oxidation or poor contact in the sensor connector

How to Fix

1. Connect the scanner, check the pressure readings - if the pressure shows 0 with the engine running, this is an anomaly
2. Visually inspect the cooling system for leaks, check the fluid level
3. Disconnect the sensor connector and measure the reference voltage (should be about 5V)
4. Check the signal wire for a short to ground with a multimeter (with the sensor disconnected)
5. Connect the sensor back, start the engine, compare the scanner readings with the real pressure (pressure gauge)
6. Replace the sensor if the wiring is in good condition; repair the wiring if a short circuit or break is detected

Related codes

Error P05C4 by Vehicle Brand