Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is having trouble talking to the battery because one of the wires is acting like it's always on when it shouldn't be.
The P1A31 code is triggered when the vehicle's control module detects a high voltage condition in the wake-up line circuit of the hybrid or electric vehicle battery.
The wake-up line is a communication line used by the vehicle's control module to 'wake up' the hybrid or EV battery system. A 'circuit high' condition indicates that the voltage on this line is higher than expected, which may disrupt communication between the control module and the battery system.
• Check Engine Light is on
• Vehicle may not start
• Reduced fuel efficiency
• Faulty wake-up line circuit
• Short to voltage in the wake-up line
• Faulty battery control module
OBD-II: On-Board Diagnostics, a standardized system in vehicles for self-diagnosing and reporting.
Circuit High: A condition where the voltage in a circuit is higher than expected.
• Use an OBD-II scanner to confirm the code.
• Inspect the wake-up line wiring for damage or shorts.
• Test the battery control module for faults.
• Repair or replace damaged wiring in the wake-up line circuit.
• Replace the battery control module if faulty.
• Clear the code and test drive the vehicle to ensure the issue is resolved.
• OBD-II scanner
• Multimeter
• Wiring repair tools
$200 - $800
Moderate
• Toyota Prius
• Chevrolet Volt
• Nissan Leaf
• Regular maintenance checks
• Ensure battery connections are secure
• Avoid exposure to extreme temperatures
Electrical Circuit Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if you experience starting issues.
Check with your vehicle manufacturer for warranty coverage on hybrid/EV components.
This code has been reported in hybrid and electric vehicles as they rely on complex electrical systems for operation.
Moderate – Address the issue soon to avoid potential starting problems.
Operating a vehicle with unresolved electrical issues may lead to safety hazards.
• Vehicle in 'ON' position
• Battery system active
The wake-up line is part of the electrical wiring connected to the battery control module, usually located near the battery pack.
Q: Can I drive my car with a P1A31 code?
A: It's not recommended as it might lead to starting issues or reduced performance.
Q: Does this code affect fuel efficiency?
A: Yes, it can lead to reduced fuel efficiency due to improper battery communication.
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