Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2020 Mazda CX-30 Base, AWDFACTORY OEM SERVICE PROCEDURE
Fuel Cut Control System Inspection
NOTE:
- This inspection has to be performed after the Fuel Injector Operation Inspection.
If data monitor function of M-MDS is used:
- Warm up the engine and idle it.
- Connect the M-MDS to the DLC-2.
- Select the ENG_RPM and the FUEL_PULSE_WD PIDs. (See PID/DATA MONITOR INSPECTION .)
- Monitor both PIDs while performing the following steps:
- Depress the accelerator pedal and increase the ENG_RPM PID to 4, 000 rpm.
- Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the FUEL_PULSE_WD PID is 0 msec, and 2-5 msec when the ENG_RPM PID drops below 1, 200 rpm.
- If not as specified, inspect the following:
- ECT sensor No. 1 and related wiring harness ECT sensor No. 2 and related wiring harness (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [SKYACTIV-G (VIN M (US))] .) (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [SKYACTIV-G (VIN L (US))] .)
- If not as specified, inspect the following:
If data monitor function of M-MDS is not used:
- Warm up the engine and idle it.
- Measure the fuel injector control signal wave profile using the oscilloscope while performing the following steps:
- Depress the accelerator pedal and increase the engine speed to 4, 000 rpm.
- Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the wave profile constant B+, and the wave appears when the engine speed drops below 1, 200 rpm. (See PCM INSPECTION [SKYACTIV-G (VIN M (US))]
.) (See PCM INSPECTION [SKYACTIV-G (VIN L (US))]
.)
- If not as specified, inspect the following:
- ECT sensor No. 1 and related wiring harness ECT sensor No. 2 and related wiring harness (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [SKYACTIV-G (VIN M (US))] .) (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [SKYACTIV-G (VIN L (US))] .)
- If not as specified, inspect the following:
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.