A problem that may cause your Mazda to not start or to run rough is a failed crankshaft position sensor.
A Mazda crankshaft position sensor (CPS) monitors the position and rotation speed of the crank shaft.
Common symptoms of bad Mazda crankshaft position sensor include:
- Mazda won't start
- Intermittent Starting
- Check Engine Light On
- Mazda cranks but won't start
- Engine idles rough
- Fault Codes: P0335, P0017, P0016
These symptoms may be intermittent in some cases. That's why it makes it hard to diagnose a bad crankshaft position sensor especially if the check engine light has not turned on.
Follow these steps to change the crankshaft position sensor on a Mazda.
You will need
- Park your Mazda on level ground. Engage parking brakes. Let the engine cool down.
- Jack up the front right (passenger) side wheel. The CPS sensor is located on the same side that you have the serpentine belt. It is not on the transmission side.
- Remove the front wheel. Make sure to secure your vehicle with a good set of jack stands and block a tire as well so your car doesn't roll.
- Remove the plastic wheel well liner. It is held in place with several plastic clips, 8mm nut, or 10 mm nuts depending on Mazda model.
- Locate the crankshaft position sensor.
- Unplug the electrical connector.
- Remove two 8mm bolts.
- Before you remove old crankshaft position sensor mark the exact position of the old sensor with a marker. You need to install the new CPS sensor in the exact same location.
- Install new crankshaft position sensor on your Mazda engine block. Notice that the mounting holes are not round but oval. This allows the sensor to be moved slightly.
- Before you tighten the screws make sure that the new sensor is in the same location as the old.
- Use the bolt in the center of the crankshaft to turn the engine until cylinder 1 hits Top Dead Center (TDC) on the compression stroke.
- You will need to align the fifth tooth to the center of the sensor magnetic tip.
- Check with your Mazda dealer as these instructions may vary between different 2.0, 2.3, 2.5 Mazda engine sizes.
If the crank sensor fails on your Mazda, your car will refuse to start or will start intermittently.
- If your Mazda is not starting it is possible that the fuel pump has failed or is not generating enough pressure.
- Spark plugs and ignition coils can also be effective and could be another reason why your Mazda does not start.