Diagnostic Procedure

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

POOR FUEL ECONOMY (SKYACTIV-G) DIAGNOSTIC PROCEDURE

Step	Inspection	Results	Action
1	VERIFY ALL SYSTEM DTCs NOTE: Display the DTCs of all the modules using the M-MDS. Perform the DTC inspection. (See DTC INSPECTION .) Are any DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
1		No	Go to the next step.
2	VERIFY IF MALFUNCTION SYMPTOM IS CAUSED BY OTHER MALFUNCTION NOTE: There are few malfunction affecting only the fuel economy, therefore it is necessary to verify that other malfunctions are not appearing as symptoms. Verify the vehicle engine condition. Can malfunction symptoms other than "POOR FUEL ECONOMY" be verified? (See SYMPTOM DIAGNOSTIC INDEX (US) .)	Yes	Go to the applicable symptom troubleshooting. (See SYMPTOM DIAGNOSTIC INDEX (US) .)
2		No	Go to the next step.
3	INSPECT ENGINE AND VEHICLE CONDITIONS NOTE: Because the vehicle malfunction cannot be verified, it is necessary to inspect the items which may be adversely affecting fuel consumption. Perform the following inspections: Engine oil level (See ENGINE OIL LEVEL INSPECTION [SKYACTIV-G (VIN M (US))] .) (See ENGINE OIL LEVEL INSPECTION [SKYACTIV-G (VIN L (US))] .) Engine oil contamination Engine coolant level (See ENGINE COOLANT LEVEL INSPECTION [SKYACTIV-G (VIN M (US))] .) (See ENGINE COOLANT LEVEL INSPECTION [SKYACTIV-G (VIN L (US))] .) Engine compression pressure inspection (See COMPRESSION INSPECTION [SKYACTIV-G (VIN M (US))] .) (See COMPRESSION INSPECTION [SKYACTIV-G (VIN L (US))] .) Spark Test (See SPARK INSPECTION [SKYACTIV-G (VIN M (US))] .) (See SPARK INSPECTION [SKYACTIV-G (VIN L (US))] .) Tire air pressure Clutch slippage (MTX) Improper ATF level (ATX) (See AUTOMATIC TRANSAXLE FLUID (ATF) INSPECTION [ET6A-EL, ET6AX-EL (US)] .) (See AUTOMATIC TRANSAXLE FLUID (ATF) INSPECTION [EV6A-EL, EV6AX-EL (US)] .) Brake dragging Is there any malfunction?	Yes	Repair or adjust the malfunctioning location and explain the repair contents to the customer based on the inspection result.
3		No	Go to the next step.
4	VERIFY VEHICLE USE CONDITION NOTE: It is necessary to ask the customer about how they use the vehicle because there is no problem with the inspection items from Step 1 to 3. Verify how the customer uses the vehicle with regard to the following applicable items, and provide the customer some pertinent advice: Tires, wheels (large size) Engine operation time is longer than traveled distance Vehicle is driven in congested traffic frequently Vehicle left idling for long periods Amount of fuel injection increases Vehicle is carrying excess items (luggage) Frequent acceleration/deceleration Frequently driving uphill Travel distances are short (engine does not warm up) Use of unrecommended engine oil (leads to inappropriate oil viscosity)	-	Symptom troubleshooting is completed.