Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car's computer is having trouble receiving a specific signal that tells it the ignition is on.
The code P16EF indicates a problem with the data reception from Terminal 15, which is related to the ignition switch signal.
P16EF is triggered when the Engine Control Module (ECM) or another control module detects an issue with the data reception from Terminal 15. Terminal 15 is responsible for providing a signal indicating the ignition is switched on. If this signal is not received correctly, it can affect various systems that rely on this information.
• Engine may not start
• Dashboard warning lights
• Intermittent electrical issues
• Faulty ignition switch
• Wiring issues or poor connections
• Faulty ECM or control module
ECM: Engine Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Check the ignition switch for proper operation.
• Inspect wiring and connectors related to Terminal 15.
• Test the ECM or control module for faults.
• Replace the ignition switch if faulty.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• Multimeter
• OBD-II scanner
• Screwdriver set
$100 - $500
Moderate
• BMW 3 Series
• Audi A4
• Volkswagen Golf
• Regularly check ignition switch operation.
• Ensure electrical connections are secure.
• Have the vehicle's computer system checked periodically.
Electrical Issue
• Avoid ignoring dashboard warning lights.
• Consult a professional mechanic if the issue persists.
Check with your vehicle manufacturer for warranty coverage on electrical components.
This code has been reported in vehicles with complex electrical systems, typically affecting European models.
Moderate – The vehicle may operate normally but could experience starting issues.
Driving with unresolved electrical issues can lead to unexpected vehicle behavior. Address the issue promptly.
• Vehicle ignition must be turned on.
• Ensure battery is fully charged.
The ignition switch is typically located on the steering column or dashboard near the steering wheel.
Q: Can I drive with a P16EF code?
A: It's not recommended as it may lead to starting issues or other electrical problems.
Q: How do I reset the P16EF code?
A: After repairs, use an OBD-II scanner to clear the code. If the issue is fixed, it should not return.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
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Universal · Torque wrench
Useful when reassembly torque matters for wheel, suspension, and under-hood fasteners.
Useful when wheel, hub, or suspension hardware needs correct reassembly torque.
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Universal · Drive-on ramps
Helpful for safer access underneath the vehicle during exhaust, EVAP, and underbody inspection work.
Helpful for safer access during underbody inspection work.
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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.