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 there is a problem with the fuel injector for cylinder 12 in your car. It's like a wire is touching something it shouldn't, causing a short circuit.
The P31BC code indicates an electrical fault where the high side of the injector circuit for cylinder 12 is shorted to the ignition coil circuit.
The P31BC code is triggered when the Engine Control Module (ECM) detects a short circuit between the high side of the hydrogen injector for cylinder 12 and the ignition coil. This can cause improper fuel delivery and misfiring in the affected cylinder.
• Engine misfire
• Poor fuel economy
• Check engine light on
• Damaged wiring harness
• Faulty injector
• Short circuit in the ignition coil
Injector: A device that delivers fuel into the engine's cylinders.
Short Circuit: An electrical circuit that allows a current to travel along an unintended path.
• Inspect the wiring harness for damage or wear.
• Check the injector for proper operation.
• Test the ignition coil for shorts.
• Repair or replace damaged wiring.
• Replace the faulty injector.
• Replace the ignition coil if necessary.
• Multimeter
• OBD-II scanner
• Wiring repair tools
$200 - $500
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regular maintenance checks
• Inspect wiring for damage
• Ensure proper installation of components
Engine Performance
• Consult a professional mechanic.
• Avoid driving long distances until fixed.
Check with the vehicle manufacturer for warranty coverage on engine components.
This code is relatively uncommon and specific to vehicles with hydrogen fuel systems.
High – This issue can cause engine performance problems and should be addressed promptly.
Driving with this code can lead to increased emissions and potential engine damage.
• Engine running
• Vehicle at operating temperature
The injector for cylinder 12 is located on the engine block, near the corresponding cylinder.
Q: Can I drive with a P31BC code?
A: It's not recommended, as it can cause engine misfires and potential damage.
Q: How can I prevent this code from occurring?
A: Regular maintenance and inspections can help prevent electrical issues.
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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.