These instructions apply to the Mazda 3 Mk4 (BP) 2019-Present. For other models, please choose your vehicle here.
Last updated:
The Mazda 3 (Mk4/BP, 2019–Present) keeps the hidden instrument-cluster Test Mode used on earlier generations, and you can open it yourself with no scan tool. Holding the trip-reset button while you switch on the ignition drops the cluster into a numbered self-test — LED and LCD checks, gauge sweeps, chimes and live sensor values — even though this generation mixes analogue dials with a central TFT screen.
What Test Mode is and what it shows
The routine runs the BP cluster through a fixed sequence of self-checks, each shown as a code number in the display. Stepping through it lets you confirm:
- Whether the dash and warning lamps switch on correctly
- Speedometer and tachometer needle sweeps, with the gauges resting at fixed test points
- Fuel-gauge and engine-temperature gauge sweeps
- Live numeric fuel level and fuel-sender readings
- The dash chime and turn-signal sound, plus button-press detection
It is the cluster checking its own gauges, lamps and the signals it receives, so a needle that refuses to sweep is a cluster fault, while one that sweeps but reads wrong in use points to the sender.
How to enter the hidden diagnostic menu
- Have the ignition fully OFF.
- Press and hold the trip-reset button on the instrument cluster.
- While holding it, set the ignition to ON so the cluster lights up. On the keyless BP, press the START button twice without pressing the brake; do not start the engine.
- Keep the trip button held until TEST appears in the odometer area, then release it.
- Tap the trip button to move through the numbered test codes.
Reading the gauges and codes
Each press advances to the next code. Begin with the lamp and display checks — a lamp that stays dark or a display fault is a cluster problem. The gauge codes drive the speedometer, tachometer, fuel and temperature needles fully across and back; watch for sticking or lag. The numeric codes show live fuel and input values, the fastest way to tell a faulty gauge from a faulty sender. Higher codes report info-display data and button-press detection. Record anything that looks off before leaving.
How to exit
Turn the ignition OFF, then back ON, to leave Test Mode. Nothing you viewed is stored or changed; the cluster runs normally afterwards.
Frequently Asked Questions
Does the TFT-screen Mazda 3 still have this? Yes. The BP keeps analogue speedo and tacho dials, so the gauge self-test and the trip-button sequence still work despite the central digital screen.
How do I reach ON without a key? Hold the trip-reset button and press the START button twice with your foot off the brake. That selects ON, and TEST will appear if you keep holding.
Will this reset the service or oil light? No. Test Mode only reads and displays data. Use the dash settings menu or the standard reset procedure for the service reminder.
Are these the same as check-engine codes? No. These are cluster-level tests and values. If the engine warning lamp is on, scan the engine ECU with an OBD-II tool.
Does it work on the Mazda 3 Skyactiv-X and turbo? Yes. All BP engine variants share the same cluster, so the sequence and gauge tests are identical.
To look up any fault code you note 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.
This website is an independent resource and is not affiliated with, endorsed by, or sponsored by Mazda. All trademarks and brand names belong to their respective owners.