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's a problem with the part of the car that helps inject fuel into cylinder 11. It's like a straw that's supposed to let fuel in, but it's not working right.
The P31D4 code indicates a fault in the electrical circuit that controls the high-pressure fuel injector for cylinder 11. The circuit is showing a low voltage or open condition.
The P31D4 code is triggered when the Engine Control Module (ECM) detects a low voltage condition in the high side circuit of the high-pressure injector for cylinder 11. This could be due to a wiring issue, a faulty injector, or a problem with the ECM itself. The high side circuit is responsible for providing the necessary voltage to activate the injector.
• Engine misfires
• Poor fuel economy
• Check engine light illuminated
• Faulty fuel injector
• Damaged wiring or connectors
• ECM malfunction
ECM: Engine Control Module, the computer that controls engine functions.
Injector: A device that sprays fuel into the engine's cylinders.
• Inspect the wiring and connectors for damage.
• Test the injector for proper operation.
• Check the ECM for fault codes and proper functionality.
• Repair or replace damaged wiring or connectors.
• Replace the faulty injector.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Fuel injector tester
$200 - $600
Moderate
• BMW 7 Series
• Mercedes-Benz S-Class
• Audi A8
• Regular maintenance checks
• Use quality fuel
• Inspect wiring regularly
Engine Performance
• Avoid driving aggressively until fixed.
• Get the vehicle inspected by a professional.
• Monitor fuel consumption for any unusual changes.
Check with your vehicle manufacturer for warranty coverage on injectors and ECM.
This code is relatively rare and is often associated with high-performance or luxury vehicles with complex fuel systems.
Moderate – This issue should be addressed soon to prevent further engine performance problems.
Driving with a malfunctioning injector can lead to increased emissions and potential engine damage.
• Engine at operating temperature
• Vehicle in park or neutral
The high-pressure injector for cylinder 11 is located on the engine block, typically near the intake manifold.
Q: Can I drive with a P31D4 code?
A: It's not recommended to drive for long periods with this code, as it can lead to engine damage.
Q: How do I reset the check engine light?
A: After repairs, use an OBD-II scanner to clear the code and reset the light.
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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.