Your Mazda’s speedometer is a valuable tool that gives you real time readings of your speed. This is necessary so you can drive safely and avoid costly speeding tickets. When your speedometer goes out, it can be frustrating, but speedometer failure is a very common issue — so many at home mechanics have figured out what to do about it. Here’s what you need to know when your speedometer isn’t working how it should.
Common Mazda Speedometer Issues
Dead speedometer: For a speedometer that isn’t working at all, or is “dead”, a bad gauge or speed sensor is almost always the problem. To test the gauge, you’ll need a voltmeter — if no read, it’s the gauge. Otherwise, the speed sensor is suspect.
Speedometer stopped working and the SES light came on: A common Mazda speedometer problem that happens when the speedometer stops working and a Service Engine Soon light appears. More times than not, your ECM is telling you that the speed sensors have stopped sending the ECM information. When this happens, replacing the speed sensor will resolve the issues.
Erratic readings from the speedometer: If you have experienced misreadings at random times, a needle that won’t settle in place, or a needle that jumps, this is known as erratic readings. Most likely, it’s an issue with the wiring, or the sensor needs to be replaced.
Changes have caused a misreading: This happens most commonly when you change the tire and wheel combination on your Mazda. Major changes like drivetrain modifications or suspension changes may also cause the speedometer to misread. The speedometer will need to be re-calibrated to fix this.
- Replacing speed sensors - For Mazdas, the speed sensors for the speedometer operate off the front wheels. You can find these sensors above the trans-axle. Remove the bolts that keep the sensor in place and replace the speed sensor and o-ring. Also, clean the housing before installing the new OEM sensor and reattach.
- Re-calibration - If your speedometer needs to be re-calibrated, it will need to be done with special software. The best place to have this done is the dealership. Some Mazda performance tuners may also be able to help you out for a small fee.