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 understanding the signals from a sensor that helps it know how the engine is running. It's like if your game console couldn't read the controller's signals properly.
The code indicates a problem with the signal from the crankshaft position sensor to the drive motor 'B' control module. This sensor helps the car's computer understand the position and speed of the crankshaft.
P1AC7 is triggered when the drive motor 'B' control module detects that the crankshaft position sensor signal is out of the expected range or not performing as expected. This sensor is crucial for timing and engine performance, as it informs the control module about the crankshaft's position and rotational speed.
• Check Engine Light is on
• Engine may run rough or misfire
• Possible decrease in fuel efficiency
• Faulty crankshaft position sensor
• Wiring issues or poor connections
• Faulty drive motor 'B' control module
Crankshaft: A shaft driven by a crank mechanism, consisting of a series of cranks and crankpins to which the connecting rods of an engine are attached.
OBD-II: On-Board Diagnostics II, a standardized system in cars and trucks for self-diagnostics and reporting.
• Use an OBD-II scanner to confirm the code.
• Inspect the crankshaft position sensor and its wiring for damage.
• Test the sensor's output with a multimeter.
• Replace the crankshaft position sensor if faulty.
• Repair or replace damaged wiring or connectors.
• Replace the drive motor 'B' control module if necessary.
• OBD-II scanner
• Multimeter
• Socket set
$150 - $500
Moderate
• Chevrolet Volt
• Cadillac ELR
• Chevrolet Spark EV
• Regularly inspect and maintain engine sensors.
• Check wiring and connections periodically.
• Ensure timely software updates for vehicle systems.
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if you're not experienced with car repairs.
Check if your vehicle's powertrain warranty covers sensor repairs.
This code has been associated with hybrid and electric vehicles where precise motor control is crucial.
Moderate – It should be addressed soon to prevent potential engine performance issues.
Driving with a malfunctioning sensor can lead to reduced performance and increased emissions, which may not comply with local regulations.
• Engine running
• Vehicle stationary
The crankshaft position sensor is typically located near the bottom of the engine, close to the crankshaft pulley.
Q: Can I drive with a P1AC7 code?
A: It's possible to drive for a short period, but it's not recommended as it may lead to further engine issues.
Q: How can I reset the Check Engine Light after fixing the issue?
A: You can use an OBD-II scanner to clear the code, or the light may turn off after several drive cycles if the issue is resolved.
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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.
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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.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
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Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.