P05C4 — Engine Coolant Pressure Sensor Circuit Low

What Does P05C4 Mean?

P05C4 is a diagnostic trouble code indicating: Engine Coolant Pressure Sensor Circuit Low. This code relates to the vehicle speed and idle control system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P05C4

⚠️ Check Engine Light (MIL) illuminated
⚠️ Engine Coolant Pressure Sensor reading at zero or minimum value
⚠️ Related system not functioning or in fail-safe mode
⚠️ Erratic idle speed

Common Causes

🔍 Open or broken wire in Engine Coolant Pressure Sensor circuit
🔍 Poor ground connection at Engine Coolant Pressure Sensor
🔍 Faulty Engine Coolant Pressure Sensor with no output signal
🔍 Disconnected or loose Engine Coolant Pressure Sensor connector
🔍 Blown fuse in related circuit

Frequently Asked Questions

What does P05C4 mean?

P05C4 indicates: Engine Coolant Pressure Sensor Circuit Low. The vehicle's computer has detected that the Engine Coolant Pressure Sensor is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P05C4?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P05C4 for extended periods may cause additional problems.

How much does it cost to fix P05C4?

Repair costs for P05C4 typically range from $20 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Repair broken wire or restore ground in Engine Coolant Pressure Sensor circuit
🔧 Clean and secure Engine Coolant Pressure Sensor connector and ground points
🔧 Replace failed Engine Coolant Pressure Sensor

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

P05C4: Engine Coolant Pressure Sensor Circuit Low