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 detected a problem with the pump that cools the motor's electronics. It thinks the pump is getting too much electricity.
The P1A85 code is triggered when the motor electronics coolant pump 'A' is receiving higher voltage than expected, causing it to shut off to prevent damage.
The motor electronics coolant pump 'A' is responsible for circulating coolant to maintain optimal temperature for electronic components. An overvoltage condition may cause the pump to shut down to protect the system from electrical damage. This can be due to a faulty voltage regulator or electrical short.
• Check engine light is on
• Overheating of motor electronics
• Reduced vehicle performance
• Faulty voltage regulator
• Electrical short in the coolant pump circuit
• Defective coolant pump
Coolant: A fluid used to prevent overheating by transferring heat away from components.
Voltage Regulator: A device that maintains a constant voltage level to electrical components.
• Check the voltage supply to the coolant pump.
• Inspect the wiring and connectors for damage or corrosion.
• Test the coolant pump for proper operation.
• Replace the voltage regulator if faulty.
• Repair or replace damaged wiring or connectors.
• Replace the coolant pump if defective.
• Multimeter
• OBD-II scanner
• Wrench set
$150 - $500
Moderate
• Chevrolet Volt
• Toyota Prius
• Nissan Leaf
• Regularly inspect electrical connections.
• Ensure proper coolant levels are maintained.
• Schedule routine vehicle maintenance.
Electrical Issue
• Avoid driving the vehicle until the issue is resolved to prevent further damage.
• Consult a professional mechanic for accurate diagnosis and repair.
Check with your vehicle manufacturer for warranty coverage on electronic components.
This code has been more prevalent in hybrid and electric vehicles due to their reliance on electronic systems.
High – Immediate attention is required to prevent potential damage to the vehicle's electronic systems.
Driving with this issue may lead to vehicle malfunction and is not recommended.
• Vehicle at operating temperature
• Electrical system fully charged
The motor electronics coolant pump is typically located near the vehicle's electronic control modules, often in the engine bay.
Q: Can I drive with a P1A85 code?
A: It is not recommended to drive with this code as it can lead to overheating of electronic components.
Q: How can I prevent a P1A85 code?
A: Regular maintenance and inspection of the vehicle's electrical and cooling systems can help prevent this issue.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.