These instructions apply to the Ford Puma Mk2 (J2K) 2020-Present.
For other models, please choose your vehicle here.
The Ford Puma (2020–present) has the same owner-accessible instrument cluster Self-Diagnostic Mode that runs across Ford’s current range, often called engineering test mode. With the Puma’s digital display you open it using the steering-wheel OK button and the ignition — no scan tool needed — for a gauge sweep, display and warning-lamp check, live engine data and any stored cluster fault codes.
What the self-test is and what it shows
This hidden routine runs the Puma’s cluster through a self-check sequence: a gauge sweep, an LCD test that exercises the digital display, and a warning-lamp check so you can spot a dead element or unlit indicator. It then steps through diagnostic and live-data screens including:
- Road speed and engine speed (RPM)
- Engine and coolant temperature in real numbers
- Battery voltage measured at the cluster
- Fuel rate and a more precise distance-to-empty
- Stored cluster Diagnostic Trouble Codes (DTCs)
It is the cluster reporting on itself and the sensors feeding it — a fast, free first look before paying a garage, and a way to verify the digital cluster hardware.
How to enter the hidden diagnostic menu
- Sit in the driver’s seat with the ignition fully OFF.
- Press and hold the OK button on the steering wheel.
- While holding OK, switch the Puma to ignition-only mode — press START once with your foot OFF the brake so accessories power up. Do not start the engine.
- Keep OK held for about five seconds, letting the welcome screen pass, until TEST appears.
- Release OK once TEST is shown.
Reading the gauges, voltage and codes
Use the steering-wheel OK and arrow buttons to step through and skip tests. Begin with the gauge sweep, LCD test and warning-lamp check — a missing element or unlit lamp points to a cluster hardware fault rather than a sensor. Continue to the live-data screens for road speed, RPM, coolant temperature, fuel rate and battery voltage. The Puma mild-hybrid (mHEV) carries a 12 V battery in the engine bay and a 48 V battery under the passenger seat; the voltage shown here is the cluster’s 12 V supply, and a healthy reading at rest is around 12.4–12.7 V. The DTC screen lists any stored cluster codes; note them before exiting.
How to exit
Turn the ignition to OFF to leave Self-Diagnostic Mode. The cluster returns to normal at the next start and nothing you viewed has been altered.
Frequently Asked Questions
Does it work on the Puma mild-hybrid and the Puma ST? Yes. The Self-Diagnostic Mode lives in the instrument cluster, so the OK-button entry is the same on the mHEV EcoBoost and the ST; their specific gauges are included in the sweep.
Is the voltage shown the 48 V hybrid battery? No. The reading is the 12 V system that powers the cluster. The 48 V battery under the passenger seat is monitored separately and is not what this screen displays.
Why won’t TEST appear? Almost always because the engine was started instead of stopping at accessory/ON, or OK was released too soon. Power up accessories only and hold OK for the full five seconds.
Will this reset the service light? No. The self-test only reads and displays; the service reminder and trip meters are untouched.
Are these the same as a check-engine scan? Not exactly — they are cluster-level codes. If an engine warning lamp is lit, run a full OBD-II scan of the engine ECU as well.
To decode any cluster trouble codes you find and judge how urgent they are, see autodtcs.com.
Independent guide — not affiliated with Ford. Always follow your official service manual and safety precautions. Read our full disclaimer.