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 helps fuel get into cylinder 12. It's like a light switch that's stuck on when it should be off.
This code indicates that the electrical circuit controlling the fuel injector for cylinder 12 is showing a higher voltage than expected.
The P3146 code is triggered when the Engine Control Module (ECM) detects an abnormally high voltage in the low side circuit of the high-pressure fuel injector for cylinder 12. This could be due to a short circuit, a faulty injector, or issues with the wiring or connectors.
• Engine misfire
• Poor fuel economy
• Check Engine Light illuminated
• Faulty fuel injector
• Short circuit in the wiring
• Damaged or corroded connectors
ECM: Engine Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for cylinder 12 injector.
• Test the injector for proper operation.
• Replace or repair damaged wiring.
• Clean or replace corroded connectors.
• Replace the faulty injector.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Audi A8
• BMW 7 Series
• Mercedes-Benz S-Class
• Regular maintenance checks
• Ensure proper fuel quality
• Inspect electrical connections periodically
Engine Performance
• Do not ignore the Check Engine Light.
• Seek professional help if unsure about DIY repairs.
Check your vehicle's warranty for coverage on fuel injectors and electrical systems.
This code is relatively rare and often associated with high-performance engines with multiple cylinders.
Moderate – Addressing this issue can prevent further engine damage.
Driving with a misfiring engine can lead to increased emissions and potential engine damage.
• Engine running
• Vehicle at operating temperature
The fuel injector for cylinder 12 is located on the engine block, typically near the intake manifold.
Q: Can I drive with a P3146 code?
A: It's not recommended to drive for long periods as it can cause engine damage.
Q: How do I reset the Check Engine Light?
A: After repairs, use an OBD-II scanner to clear the code.
High-End · Full-system diagnostics
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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.