Severity High
P0C42

Hybrid Battery Pack Coolant Temperature Sensor Circuit Malfunction

📅 Last reviewed: July 2026
What does the P0C42 code mean?

The P0C42 code indicates a problem in the circuit of the hybrid battery pack coolant temperature sensor. This sensor monitors the temperature of the coolant that cools the high-voltage hybrid battery. When the sensor or its circuit fails, the hybrid control system may not accurately read battery temperature, potentially leading to reduced performance, increased emissions, or battery damage. Common causes include a faulty sensor, wiring issues, or a defective hybrid battery control module.

High
Severity
$50-$150
Typical Cost
High
Frequency

1. Symptoms You Will Notice

2. Most Common Causes

3. Step-by-Step Diagnosis

1

Step 1: Use an OBD2 scanner to confirm the code and check for additional codes.

2

Step 2: Visually inspect the coolant temperature sensor and its wiring for damage, corrosion, or loose connections.

3

Step 3: Test the sensor's resistance and compare to manufacturer specifications.

4

Step 4: Check the circuit for continuity and shorts using a multimeter.

5

Step 5: If all else is fine, test the hybrid battery control module or consult a professional.

4. Frequently Asked Questions

Is it safe to drive with this code?

It is not recommended to drive with this code as it can lead to battery overheating or reduced performance. Have it diagnosed promptly.

How much does it cost to fix?

The cost typically ranges from $50 to $150 for sensor replacement, but can be higher if wiring repairs or module replacement is needed.

5. Commonly Affected Makes

This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.

6. Related Codes

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