Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Engine Running Diagnostic Mode
For Aviator and Explorer,
The green READY indicator flashing once every 3 seconds indicates the vehicle is in the engine running.
- Apply the parking brake
- Place the gear selector in the PARK position
- Ignition in the OFF position
- Ignition in the ON position with the engine OFF
- Within 5 seconds of the ignition in the ON position, fully apply the accelerator and brake pedals, hold the accelerator and brake pedals fully applied for 10 seconds
- Within 5 seconds, release the accelerator pedal, cycle the ignition to the ON/RUN position, fully apply the accelerator pedal and hold the engine RPM at the REV limiter, approximately 4,000 RPM, for 10 seconds until the green READY indicator turns OFF, then release the accelerator pedal
If the green READY indicator does not turn off after 10 seconds, cycle the ignition to the off position. Allow the vehicle enough time for all the modules to power down then procedure can be repeated.
For all others,
The engine running diagnostic mode is a powertrain control module (PCM) strategy which is separate from the normal operating strategy. When in this mode, the engine is running and does not turn off, as it does during normal operation. The engine RPM may be increased to the desired speed as the vehicle is in the pedal follower mode. To activate the engine running diagnostic mode the gear selector must be in the PARK position, and the ignition cycled to the START position. The engine is allowed to idle as long as the powertrain and hybrid electric systems operate within the calibrated limits. This mode is helpful whenever the engine must stay running for diagnostics and repairs that require the engine to be idling for extended time. Carry out the following sequence to activate this mode:
- apply the parking brake
- place the gear selector in the PARK position
- ignition in the OFF position
- Ignition in the ON position with the engine OFF
- Within 5 seconds of the ignition in the ON position, fully apply the accelerator pedal and hold for 10 seconds
- Within 5 seconds release the accelerator pedal, shift the gear selector to the DRIVE position and fully apply the accelerator pedal
- Hold the accelerator pedal fully applied for 10 seconds
- Release the accelerator pedal and shift the gear selector to the PARK position
If the sequence is correctly executed the powertrain malfunction indicator (wrench) flashes once per second when the gear selector is shifted to the PARK position. The engine may be started by cycling the ignition to the START position. The PCM exits the engine running mode when the gear selector is shifted to any gear other than PARK, when the ignition is turned to the OFF or ACC position, or the powertrain or hybrid electric system exceeds calibrated limits.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.