POOR FUEL ECONOMY [SKYACTIV-G]

SM2334615

id0103s4890100

Troubleshooting item	Poor fuel economy
Description	• The fuel consumption is high compared to the customer’s expectations or the previous fuel consumption.
Possible cause	Note • The perceived poor fuel economy condition has two causes; the vehicle conditions and how the driver uses the vehicle. Especially, it relies heavily on how the driver uses the vehicle. • Engine oil malfunction ― Improper engine oil level ― Engine oil contamination ― Improper engine oil viscosity • Improper engine compression • Ignition system malfunction • Improper engine coolant level • Improper tire air pressure • Improper tires, wheels (large size, irregular size) • Clutch slippage (MTX) • Improper ATF level (ATX) • Brake dragging • 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)

Troubleshooting item

Poor fuel economy

Description

• The fuel consumption is high compared to the customer’s expectations or the previous fuel consumption.

Possible cause

Note

• The perceived poor fuel economy condition has two causes; the vehicle conditions and how the driver uses the vehicle. Especially, it relies heavily on how the driver uses the vehicle.

• Engine oil malfunction

― Improper engine oil level

― Engine oil contamination

― Improper engine oil viscosity

• Improper engine compression

• Ignition system malfunction

• Improper engine coolant level

• Improper tire air pressure

• Improper tires, wheels (large size, irregular size)

• Clutch slippage (MTX)

• Improper ATF level (ATX)

• Brake dragging

• 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)

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?	Yes	Go to the applicable symptom troubleshooting. (See SYMPTOM DIAGNOSTIC INDEX [SKYACTIV-G (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 (WITH CYLINDER DEACTIVATION (US))].) (See ENGINE OIL LEVEL INSPECTION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (US))].) ― Engine oil contamination ― Engine coolant level (See ENGINE COOLANT LEVEL INSPECTION [SKYACTIV-G (WITH CYLINDER DEACTIVATION (US))].) (See ENGINE COOLANT LEVEL INSPECTION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (US))].) ― Engine compression pressure inspection (See COMPRESSION INSPECTION [SKYACTIV-G (WITH CYLINDER DEACTIVATION (US))].) (See COMPRESSION INSPECTION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (US))].) ― Spark Test (See SPARK INSPECTION [SKYACTIV-G (WITH CYLINDER DEACTIVATION (US))].) (See SPARK INSPECTION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (US))].) ― Tire air pressure ― Clutch slippage (MTX) ― Improper ATF level (ATX) (See AUTOMATIC TRANSAXLE FLUID (ATF) INSPECTION [ET6A-EL (US)].) (See AUTOMATIC TRANSAXLE FLUID (ATF) INSPECTION [EV6A-EL, EV6AX-EL].) (See AUTOMATIC TRANSAXLE FLUID (ATF) INSPECTION [ET6A-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.

2019 BP Shop Manual

BP Shop Manual

POOR FUEL ECONOMY [SKYACTIV-G]

POOR FUEL ECONOMY [SKYACTIV-G]