Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer is saying that something is wrong with the part that controls how much fuel goes into one of the engine's cylinders. It's like a faucet that's stuck open and letting too much water through.
This code indicates a problem with the electrical circuit that controls the fuel injector for cylinder 10. The circuit is showing higher than normal voltage.
The P31AA code is triggered when the Engine Control Module (ECM) detects a high voltage condition in the low side circuit of the hydrogen injector for cylinder 10. This could be due to a short circuit, faulty wiring, or a malfunctioning injector.
• Check Engine Light is on
• Engine misfire
• Reduced engine performance
• Faulty fuel injector
• Short circuit in wiring
• Malfunctioning ECM
ECM: Engine Control Module
Injector: A device that sprays fuel into the engine's cylinders
• Use an OBD-II scanner to confirm the code
• Inspect the wiring and connectors for damage
• Test the injector for proper operation
• Replace the faulty injector
• Repair or replace damaged wiring
• Reprogram or replace the ECM if necessary
• OBD-II scanner
• Multimeter
• Injector tester
$200 - $600
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regular maintenance checks
• Inspect wiring for wear
• Use quality fuel
Engine Performance
• Do not ignore the Check Engine Light
• Seek professional help if unsure
• Avoid driving long distances until fixed
Check with your vehicle manufacturer for warranty coverage on engine components.
This code is relatively uncommon and often associated with specific vehicle models using hydrogen fuel systems.
High – Immediate attention is recommended to prevent engine damage.
Driving with this issue may lead to engine damage and is not advised.
• Engine at operating temperature
• Vehicle in park or neutral
The injector is located on the engine, near cylinder 10.
Q: Can I drive with a P31AA code?
A: It's not recommended as it may lead to further engine damage.
Q: What happens if I ignore this code?
A: Ignoring the code can result in poor engine performance and potential damage.
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A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
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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.