Q: Mazda 3 has no spark and won't start

Hi there. It sounds like there could be a fault somewhere in the camshaft position sensor, crankshaft position sensor, or engine computer circuit. Check all fuses and relays and replace as necessary.

The computer will not enable spark to the cylinders if it missing the signal from one or both of the position sensors. Inspect the wire harness and connectors for damage or looseness and correct as necessary. If one or both of the sensors has been dropped, hit, or damaged, the sensor may be in need of replacement. Check for a reference voltage at the connector to both sensors. If there is no damage and the sensors tests OK, then there could be a fault in the engine computer. I strongly suggest acquiring a qualified technician to perform an inspection to prevent the replacement of unnecessary parts.

If you would like to have an expert scope this out, then a certified technician from YourMechanic can come to your car’s location to diagnose the no start so that this can be repaired properly.