14

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.

• Use of inferior fuel

• Ethanol blended

• Lower octane

• 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, irregular size)

• Improper wheel alignment

• Clutch slippage (MT)

• Improper ATF level (AT)

• 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)

STEP

INSPECTION

RESULTS

ACTION

1

NOTE:

• Display the DTCs of all the modules using the M-MDS.

• Connect the M-MDS to the DLC-2.

• After the vehicle is identified, select the following items from the initialization screen of the M-MDS.

• Select “Self Test”.

• Select “All CMDTCs”.

• Verify the DTC according to the directions on the screen.

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.

No

Go to the next step.

2

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 “NO.14 POOR FUEL ECONOMY” be verified?

Yes

Go to the applicable symptom troubleshooting.

(See SYMPTOM DIAGNOSTIC INDEX [SKYACTIV-G 2.0].)

No

Go to the next step.

3

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:

• Use of inferior fuel

• Engine oil level

  (See ENGINE OIL LEVEL INSPECTION [SKYACTIV-G 2.0].)

• Engine oil contamination

• Engine coolant level

  (See ENGINE COOLANT LEVEL INSPECTION [SKYACTIV-G 2.0].)

• Engine compression pressure inspection

  (See COMPRESSION INSPECTION [SKYACTIV-G 2.0].)

• Spark Test

  (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.0].)

• Tire air pressure

• Wheel alignment

  (See SUSPENSION TECHNICAL DATA.)

• Clutch slippage (MT)

• Improper ATF level (AT)

  (See AUTOMATIC TRANSMISSION FLUID (ATF) LEVEL ADJUSTMENT [SJ6A-EL].)

• 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.

No

Go to the next step.

4

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)

• Driving frequently at high-altitude

• Driving frequently during strong winds

• Use of unrecommended engine oil (leads to inappropriate oil viscosity)

—

Symptom troubleshooting is completed.