These instructions apply to the Mazda 6 Mk3 (GJ/GL) 2012-Present. For other models, please choose your vehicle here.
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The Mazda 6 (Mk3/GJ–GL, 2012–Present) has a built-in instrument-cluster Test Mode you can open yourself with no scan tool. Holding the dash trip-reset button while you switch the ignition to ON drops the cluster into a numbered self-test — gauge sweeps, warning-lamp and LCD checks, chimes and live sensor values — giving you a quick, free first look before paying for diagnostics.
What Test Mode is and what it shows
This routine runs the GJ/GL cluster through a fixed sequence of self-checks, each marked by a code number in the odometer window. As you step through it you can confirm:
- Each warning and indicator LED switching on in turn
- The LCD segments, backlight and dash illumination
- Full needle sweeps of the speedometer and tachometer
- Fuel-gauge and coolant-temperature gauge sweeps
- Live numeric fuel-sender values and the warning and turn-signal chimes
The cluster is testing its own gauges and the signals it receives, so a needle that will not sweep is a cluster fault, while one that sweeps fine but misreads on the road points to the sender or its wiring.
How to enter the hidden diagnostic menu
- Switch the ignition fully OFF.
- Press and hold the trip-reset button on the cluster.
- While holding it, set the ignition to ON. On keyless cars press the START button twice without pressing the brake pedal; do not start the engine.
- Keep the trip button held until TEST shows in the odometer display, then release it.
- Press the trip button to step through the numbered tests.
Reading the gauges and codes
Each press advances to the next code. Start with the LED and LCD checks — a dead lamp or missing display segment is a cluster hardware fault. The gauge codes drive the speedometer, tachometer, fuel and temperature needles through their full travel; look for sticking or lag. Numeric codes report live fuel-sender and input values, which is the fastest way to separate a faulty gauge from a faulty sender. Note any abnormal code or reading before you exit.
How to exit
Turn the ignition OFF, or press the START button to quit, then cycle back ON for normal use. Viewing the tests changes nothing, and the cluster behaves normally at the next start.
Frequently Asked Questions
How do I enter ON on a keyless Mazda 6? Hold the trip-reset button and press the START button twice without touching the brake. That selects ON, and the cluster shows TEST if you keep holding.
Does this work on the Mazda 6 wagon and sedan? Yes. Both Tourer and saloon GJ/GL bodies use the same cluster and trip-button sequence.
Will it reset my service indicator? No. Test Mode only reads and displays data; it does not touch the service reminder or trip meters.
Are these cluster codes the same as engine fault codes? No. They are cluster-level tests and values. If the check-engine lamp is on, scan the engine ECU with an OBD-II tool instead.
Why does TEST flash and disappear? You reached START or ENGINE-RUN rather than ON, or released the button too soon. Reach ON only, keep the trip button held, and wait for TEST.
To decode any fault code you record here, visit autodtcs.com.
Disclaimer: The information on this page is provided for general guidance only. Always follow your official service manual and safety precautions when working on your vehicle. We are not responsible for errors, omissions, or any damage resulting from the use of this information.
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