Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the part of the car that helps keep the battery cool. It's like when a fan stops working in your computer, and it gets too hot.
The P1B37 code indicates that the voltage in the circuit controlling the battery coolant valve and chiller is higher than expected.
The P1B37 code is triggered when the Powertrain Control Module (PCM) detects an unusually high voltage in the hybrid or electric vehicle's battery coolant valve to chiller circuit. This circuit is responsible for regulating the flow of coolant to maintain optimal battery temperatures.
• Check Engine Light is on
• Overheating of the hybrid/EV battery
• Reduced vehicle performance
• Faulty battery coolant valve
• Wiring issues or poor connections in the circuit
• Malfunctioning chiller or control module
PCM: Powertrain Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to confirm the code.
• Inspect the battery coolant valve and associated wiring for damage.
• Test the voltage and continuity of the circuit.
• Replace the faulty battery coolant valve.
• Repair or replace damaged wiring or connectors.
• Replace the chiller or control module if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$200 - $800
Moderate
• Chevrolet Volt
• Toyota Prius
• Nissan Leaf
• Regular maintenance checks of the cooling system.
• Ensure proper coolant levels and quality.
• Inspect electrical connections periodically.
Sensor Issue
• Do not ignore the Check Engine Light.
• Seek professional diagnosis if unsure.
• Monitor vehicle performance for any changes.
Check with your vehicle manufacturer; hybrid components may have extended warranties.
This code has become more common as hybrid and EV vehicles have increased in popularity, highlighting the importance of battery cooling systems.
Moderate – Addressing this issue is important to prevent battery damage.
Ignoring this code can lead to reduced battery life and potential safety risks. Always ensure repairs are done by qualified personnel.
• Vehicle must be in a safe environment.
• Ensure the vehicle is off before inspecting components.
The battery coolant valve and chiller are typically located near the vehicle's battery pack, often in the rear or undercarriage of the vehicle.
Q: Can I drive my car with this code?
A: It's not recommended to drive for extended periods as it may lead to battery overheating.
Q: How often should I check the coolant system?
A: Regularly during scheduled maintenance or if you notice performance issues.
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.