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 something is wrong with the fuel injector for cylinder 6 in the engine. It's not working as it should, and this affects how the car runs.
The error indicates a timing issue with the low side booster of the high-pressure injector for cylinder 6.
The P3123 code is triggered when the Engine Control Module (ECM) detects a timing error in the low side booster circuit of the high-pressure fuel injector for cylinder 6. This can affect the fuel delivery timing and efficiency, potentially causing performance issues.
• Engine misfire
• Reduced engine performance
• Check Engine Light illuminated
• Faulty fuel injector
• Wiring issues in the injector circuit
• Defective ECM
ECM: Engine Control Module, the computer that controls engine functions.
Injector: A component that sprays fuel into the engine's cylinders.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for cylinder 6 injector.
• 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
• Fuel injector tester
$200 - $600
Moderate
• BMW 3 Series
• Audi A4
• Ford F-150
• Regular maintenance and inspection of fuel injectors
• Using high-quality fuel
• Keeping the fuel system clean
Engine Performance
• Avoid driving the vehicle until the issue is resolved to prevent further damage.
• Consult a professional mechanic for accurate diagnosis and repair.
Check with your vehicle manufacturer for warranty coverage on fuel injectors.
This code has been associated with injector timing issues in vehicles with direct injection systems.
High – This issue can lead to engine performance problems and should be addressed promptly.
Driving with an engine misfire can cause damage to the catalytic converter and increase emissions.
• Engine at operating temperature
• Vehicle in idle or under load
The fuel injector for cylinder 6 is located on the engine block, typically on the passenger side for inline engines or under the intake manifold for V-type engines.
Q: Can I drive with a P3123 code?
A: It's not recommended as it can lead to further engine damage and reduced performance.
Q: How can I prevent this code from occurring?
A: Regular maintenance and using quality fuel can help prevent injector-related 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.