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 computer in your car is not getting enough power to control the fuel injectors on one side of the engine.
The Engine Control Module (ECM) is detecting a low voltage condition in the high-pressure fuel injector circuit on bank 2 of the engine.
P31E3 H2 indicates that the ECM has detected a voltage level below the expected threshold for the high-pressure injector supply circuit in bank 2. This can affect the injector's ability to deliver the correct amount of fuel, potentially leading to engine performance issues.
• Check Engine Light is on
• Engine misfires
• Reduced engine performance
• Faulty injector control module
• Wiring issues such as shorts or open circuits
• Poor electrical connections
ECM: Engine Control Module
Injector: A device that sprays fuel into the engine's cylinders
• Use a multimeter to check the voltage at the injector connectors.
• Inspect wiring and connectors for damage or corrosion.
• Test the injector control module for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the injector control module if faulty.
• Ensure all electrical connections are secure and free of corrosion.
• Multimeter
• OBD-II scanner
• Basic hand tools
$200 - $600
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regular maintenance checks on electrical systems
• Ensure connectors are clean and secure
• Avoid exposure of electrical components to moisture
Electrical Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Avoid driving the vehicle hard until the issue is resolved.
Check with your vehicle manufacturer; some components may be covered under warranty.
This code has been associated with issues in vehicles with complex fuel injection systems, particularly in models with advanced ECMs.
Moderate – While the vehicle may still be drivable, it could lead to more severe engine issues if not addressed.
Driving with a known issue can lead to engine damage and may not comply with emissions regulations.
• Engine running
• Vehicle in a safe, stationary position
The high-pressure injectors are typically located on the engine's cylinder head, with the ECM usually found in the engine bay or under the dashboard.
Q: Can I drive with a P31E3 H2 code?
A: It's not recommended to drive for extended periods as it can lead to engine damage.
Q: What does Bank 2 mean?
A: Bank 2 refers to the side of the engine opposite to where cylinder 1 is located.
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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.