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 thinks there's a problem with the sensor that measures the high voltage current in the charging system. It thinks the current is too high, which might not be true.
The car's control module monitors the current sensor in the DC/DC converter. If the sensor reports an unusually high current that doesn't match expected values, this code is triggered.
The P1C78 code indicates that the Universal Charger Extension Control Module has detected an implausible high reading from the high voltage current sensor in the DC/DC converter circuit. This could be due to a sensor fault, wiring issue, or a problem with the control module itself.
• Check Engine Light is on
• Possible charging issues
• Reduced vehicle performance
• Faulty high voltage current sensor
• Wiring issues or poor connections
• Malfunctioning Universal Charger Extension Control Module
DC/DC Converter: A device that converts direct current (DC) from one voltage level to another.
Current Sensor: A device that measures the flow of electric current.
• Inspect the wiring and connectors for damage or corrosion.
• Test the high voltage current sensor for proper operation.
• Check the Universal Charger Extension Control Module for faults.
• Repair or replace damaged wiring or connectors.
• Replace the high voltage current sensor if faulty.
• Replace or reprogram the Universal Charger Extension Control Module if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Chevrolet Volt
• Nissan Leaf
• Toyota Prius
• Regular maintenance checks
• Ensure all electrical connections are secure
• Monitor for any unusual electrical behavior
Sensor Issue
• Do not ignore the warning light.
• Have the vehicle checked by a professional as soon as possible.
Check with the vehicle manufacturer for warranty coverage on electrical components.
This code has been reported in hybrid and electric vehicles where the charging system is more complex.
Moderate – It should be addressed soon to avoid potential charging issues.
Driving with a malfunctioning charging system can lead to reduced performance and potential safety risks.
• Vehicle must be in a safe, stationary position.
• Ensure the battery is adequately charged before testing.
The high voltage current sensor is typically located near the DC/DC converter in the engine bay.
Q: Can I drive with a P1C78 code?
A: It's not recommended to drive for extended periods with this code, as it may affect the vehicle's charging system.
Q: How do I reset the P1C78 code?
A: After repairs, use an OBD-II scanner to clear the code. If the issue persists, further diagnosis is needed.
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