NO.16 POOR FUEL ECONOMY [MZR-CD 2.2]

16	POOR FUEL ECONOMY
DESCRIPTION	• Fuel economy is unsatisfactory.
POSSIBLE CAUSE	• Incorrect idle speed • Improper operation of A/C system • Intake-air system restriction or clogging • Engine cooling system malfunction • Poor fuel quality • Improper coolant level • Erratic signal from CKP sensor • Erratic signal from CMP sensor • Fuel pressure sensor or related circuit malfunction • ECT sensor or related circuit malfunction • Boost sensor or related circuit malfunction • APP sensor or related circuit malfunction • MAF/IAT sensor or related circuit malfunction • IAT sensor No.2 or related circuit malfunction • VSS or related circuit malfunction • Turbocharger malfunction • Charge air cooler malfunction • Low engine compression • Improper valve timing • Exhaust system and/or oxidation catalytic converter clogging • Incorrect fuel injection timing • Fuel injector malfunction • Supply pump malfunction • Fuel leakage • Fuel line clogging or restriction • Fuel filter clogging or restriction • Brake dragging • EGR system malfunction • Vacuum leakage • Clutch slippage • VBC system malfunction ― Guide blade actuator position sensor malfunction • Coolant heater system malfunction • Fuel injection learning improper Warning The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: • Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. • Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE SERVICE PRECAUTION” and “AFTER SERVICE PRECAUTION” described in this manual. (See BEFORE SERVICE PRECAUTION [MZR-CD 2.2].) (See AFTER SERVICE PRECAUTION [MZR-CD 2.2].)

POOR FUEL ECONOMY

DESCRIPTION

• Fuel economy is unsatisfactory.

POSSIBLE CAUSE

• Incorrect idle speed

• Improper operation of A/C system

• Intake-air system restriction or clogging

• Engine cooling system malfunction

• Poor fuel quality

• Improper coolant level

• Erratic signal from CKP sensor

• Erratic signal from CMP sensor

• Fuel pressure sensor or related circuit malfunction

• ECT sensor or related circuit malfunction

• Boost sensor or related circuit malfunction

• APP sensor or related circuit malfunction

• MAF/IAT sensor or related circuit malfunction

• IAT sensor No.2 or related circuit malfunction

• VSS or related circuit malfunction

• Turbocharger malfunction

• Charge air cooler malfunction

• Low engine compression

• Improper valve timing

• Exhaust system and/or oxidation catalytic converter clogging

• Incorrect fuel injection timing

• Fuel injector malfunction

• Supply pump malfunction

• Fuel leakage

• Fuel line clogging or restriction

• Fuel filter clogging or restriction

• Brake dragging

• EGR system malfunction

• Vacuum leakage

• Clutch slippage

• VBC system malfunction

― Guide blade actuator position sensor malfunction

• Coolant heater system malfunction

• Fuel injection learning improper

Warning

The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services:

• Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.

• Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE SERVICE PRECAUTION” and “AFTER SERVICE PRECAUTION” described in this manual. (See BEFORE SERVICE PRECAUTION [MZR-CD 2.2].) (See AFTER SERVICE PRECAUTION [MZR-CD 2.2].)

STEP	INSPECTION	RESULTS	ACTION
1	Inspect the following: • Fuel quality (e.g.: including water contamination, winter/summer blend) • Fuel line/fuel filter clogging and/or restriction • Fuel line leakage • Intake-air system restriction • Exhaust system and/or oxidation catalytic converter restriction • Charge air cooler condition (restriction or damaged) • Vacuum leakage Are all items normal?	Yes	Go to the next step.
No	Service if necessary. Repeat Step 1.
2	Is the brake system functioning properly?	Yes	Go to the next step.
No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
3	Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST [MZR-CD 2.2].) Are any DTCs displayed?	Yes	DTC is displayed: • Go to the applicable DTC inspection. (See DTC TABLE [MZR-CD 2.2].) Communication error message is displayed: • Open circuit in wiring harness between main relay terminal E and PCM terminal 2I • Open circuit in wiring harness between main relay terminal C and PCM terminals 2C, 2F • Main relay is stuck open. • Open or poor ground circuit (PCM terminals 2A, 2B, 2D and 2E) • Poor connection of vehicle body ground
No	Go to the next step.
4	Start and warm up the engine to normal operating temperature. Verify the diesel particulate filter indicator light condition. Does the diesel particulate filter indicator light illuminate or flash?	Yes	Diesel particulate filter indicator light illuminates: • Perform the manual diesel particulate filter regeneration procedure. (See DIESEL PARTICULATE FILTER REGENERATION [MZR-CD 2.2].) Diesel particulate filter indicator light flashes: • Go to the symptom troubleshooting “NO.4 DIESEL PARTICULATE FILTER INDICATOR LIGHT FLASHES”. (See NO.4 DIESEL PARTICULATE FILTER INDICATOR LIGHT FLASHES [MZR-CD 2.2].)
No	Go to the next step.
5	Note • If the following test cannot be performed due to engine stalling, go to the next step. Connect the pressure gauge to the A/C line. Turn the blower and A/C switches on. Is the pressure within the specification?	Yes	Go to the next step.
No	If the A/C is always on: • Go to the symptom troubleshooting “NO.26 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”. (See NO.26 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR-CD 2.2].) For other symptoms: • Inspect the following: ― Refrigerant charging amount ― Cooling fan operation • Repair or replace the malfunctioning part according to the inspection results.
6	Caution • While performing this step, always operate the vehicle in a safe and lawful manner. • When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR-CD 2.2].) Drive the vehicle while monitoring the ECT PID. Is the ECT PID value within the specification? (See PCM INSPECTION [MZR-CD 2.2].)	Yes	Go to the next step.
No	Inspect the following: • Coolant leakage • Cooling fan operation • Thermostat operation Repair or replace the malfunctioning part according to the inspection results.
7	Inspect the idle speed. (See ENGINE TUNE-UP [MZR-CD 2.2].) Is there any malfunction?	Yes	Go to the symptom troubleshooting “NO.9 SLOW RETURN TO IDLE”. (See NO.9 SLOW RETURN TO IDLE [MZR-CD 2.2].)
No	Go to the next step.
8	Perform the EGR Valve Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR-CD 2.2].) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
9	Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZR-CD 2.2].) Is there any malfunction?	Yes	Replace the accelerator pedal component. (See ACCELERATOR PEDAL COMPONENT REMOVAL/INSTALLATION [MZR-CD 2.2].)
No	Go to the next step.
10	Inspect the engine compression. (See COMPRESSION INSPECTION [MZR-CD 2.2].) Is there any malfunction?	Yes	Inspect the following: • Damaged valve seat • Worn valve stem and valve guide • Worn or stuck piston ring • Worn piston, piston ring or cylinder • Improper valve timing Service if necessary.
No	Go to the next step.
11	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZR-CD 2.2].) Is there any malfunction?	Yes	Replace the fuel injector. (See FUEL INJECTOR REMOVAL/INSTALLATION [MZR-CD 2.2].)
No	Go to the next step.
12	Inspect the turbocharger. (See TURBOCHARGER INSPECTION [MZR-CD 2.2].) Is there any malfunction?	Yes	Replace the turbocharger. (See EXHAUST SYSTEM REMOVAL/INSTALLATION [MZR-CD 2.2].)
No	Go to the next step.
13	Access the following PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZR-CD 2.2].) • VBC_POS • VBCV Command VBCV PID from 0 to 100 % using the simulation function. Does the VBC_POS PID value change according to the VBCV commanded value?	Yes	Go to Step 15.
No	Go to the next step.
14	Perform the Guide Blade Actuator Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR-CD 2.2].) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
15	Visually inspect the CKP sensor and teeth of pulse wheel. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZR-CD 2.2].) Are the CKP sensor and teeth of pulse wheel normal?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
16	Visually inspect the CMP sensor and teeth of pulse wheel. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZR-CD 2.2].) Are the CMP sensor and teeth of pulse wheel normal?	Yes	Access the following PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZR-CD 2.2].) (See PCM INSPECTION [MZR-CD 2.2].) • ECT • IAT • MAF • MAP • RPM • VSS ― If the PID value is not normal: • Repair or replace the malfunctioning part according to the inspection results. ― If the PID value is normal: • Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
17	Inspect the timing chain for the following: • Chipping of gear teeth • Low tension • Breakage damage or cracks Is there any malfunction?	Yes	If the valve timing is incorrect: • Adjust the valve timing. If the timing chain is not normal: • Replace the timing chain. (See TIMING CHAIN REMOVAL/INSTALLATION [MZR-CD 2.2].)
No	Inspect the following: • Clutch slippage • CKP sensor • Boost sensor and related circuit • Brake system for dragging • Coolant heater system • Glow system ― If there is any malfunction: • Repair or replace the malfunctioning part according to the inspection results. ― If there is no malfunction: • Remove the supply pump. (See SUPPLY PUMP REMOVAL/INSTALLATION [MZR-CD 2.2].) • Inspect the supply pump. (See SUPPLY PUMP INSPECTION [MZR-CD 2.2].) • Repair or replace the malfunctioning part according to the inspection results.
18	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR-CD 2.2].) • If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis. ― If the vehicle is repaired, troubleshooting is completed. ― If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP

INSPECTION

RESULTS

ACTION

Inspect the following:

• Fuel quality (e.g.: including water contamination, winter/summer blend)

• Fuel line/fuel filter clogging and/or restriction

• Fuel line leakage

• Intake-air system restriction

• Exhaust system and/or oxidation catalytic converter restriction

• Charge air cooler condition (restriction or damaged)

• Vacuum leakage

Are all items normal?

Yes

Go to the next step.

Service if necessary.

Repeat Step 1.

Is the brake system functioning properly?

Yes

Go to the next step.

Inspect for cause.

Repair or replace the malfunctioning part according to the inspection results.

Perform the KOEO or KOER self test.

(See KOEO/KOER SELF TEST [MZR-CD 2.2].)

Are any DTCs displayed?

Yes

DTC is displayed:

• Go to the applicable DTC inspection.

(See DTC TABLE [MZR-CD 2.2].)

Communication error message is displayed:

• Open circuit in wiring harness between main relay terminal E and PCM terminal 2I

• Open circuit in wiring harness between main relay terminal C and PCM terminals 2C, 2F

• Main relay is stuck open.

• Open or poor ground circuit (PCM terminals 2A, 2B, 2D and 2E)

• Poor connection of vehicle body ground

Go to the next step.

Start and warm up the engine to normal operating temperature.

Verify the diesel particulate filter indicator light condition.

Does the diesel particulate filter indicator light illuminate or flash?

Yes

Diesel particulate filter indicator light illuminates:

• Perform the manual diesel particulate filter regeneration procedure.

(See DIESEL PARTICULATE FILTER REGENERATION [MZR-CD 2.2].)

Diesel particulate filter indicator light flashes:

• Go to the symptom troubleshooting “NO.4 DIESEL PARTICULATE FILTER INDICATOR LIGHT FLASHES”.

(See NO.4 DIESEL PARTICULATE FILTER INDICATOR LIGHT FLASHES [MZR-CD 2.2].)

Go to the next step.

Note

• If the following test cannot be performed due to engine stalling, go to the next step.

Connect the pressure gauge to the A/C line.

Turn the blower and A/C switches on.

Is the pressure within the specification?

Yes

Go to the next step.

If the A/C is always on:

• Go to the symptom troubleshooting “NO.26 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”.

(See NO.26 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR-CD 2.2].)

For other symptoms:

• Inspect the following:

― Refrigerant charging amount

― Cooling fan operation

• Repair or replace the malfunctioning part according to the inspection results.

Caution

• While performing this step, always operate the vehicle in a safe and lawful manner.

• When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later.

Access the ECT PID using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR-CD 2.2].)

Drive the vehicle while monitoring the ECT PID.

Is the ECT PID value within the specification?

(See PCM INSPECTION [MZR-CD 2.2].)

Yes

Go to the next step.

Inspect the following:

• Coolant leakage

• Cooling fan operation

• Thermostat operation

Repair or replace the malfunctioning part according to the inspection results.

Inspect the idle speed.

(See ENGINE TUNE-UP [MZR-CD 2.2].)

Is there any malfunction?

Yes

Go to the symptom troubleshooting “NO.9 SLOW RETURN TO IDLE”.

(See NO.9 SLOW RETURN TO IDLE [MZR-CD 2.2].)

Go to the next step.

Perform the EGR Valve Operation Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR-CD 2.2].)

Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Inspect the APP sensor.

(See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZR-CD 2.2].)

Is there any malfunction?

Yes

Replace the accelerator pedal component.

(See ACCELERATOR PEDAL COMPONENT REMOVAL/INSTALLATION [MZR-CD 2.2].)

Go to the next step.

Inspect the engine compression.

(See COMPRESSION INSPECTION [MZR-CD 2.2].)

Is there any malfunction?

Yes

Inspect the following:

• Damaged valve seat

• Worn valve stem and valve guide

• Worn or stuck piston ring

• Worn piston, piston ring or cylinder

• Improper valve timing

Service if necessary.

Go to the next step.

Inspect the fuel injector.

(See FUEL INJECTOR INSPECTION [MZR-CD 2.2].)

Is there any malfunction?

Yes

Replace the fuel injector.

(See FUEL INJECTOR REMOVAL/INSTALLATION [MZR-CD 2.2].)

Go to the next step.

Inspect the turbocharger.

(See TURBOCHARGER INSPECTION [MZR-CD 2.2].)

Is there any malfunction?

Yes

Replace the turbocharger.

(See EXHAUST SYSTEM REMOVAL/INSTALLATION [MZR-CD 2.2].)

Go to the next step.

Access the following PIDs using the M-MDS:

(See ON-BOARD DIAGNOSTIC TEST [MZR-CD 2.2].)

• VBC_POS

• VBCV

Command VBCV PID from 0 to 100 % using the simulation function.

Does the VBC_POS PID value change according to the VBCV commanded value?

Yes

Go to Step 15.

Go to the next step.

Perform the Guide Blade Actuator Operation Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR-CD 2.2].)

Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Visually inspect the CKP sensor and teeth of pulse wheel.

(See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZR-CD 2.2].)

Are the CKP sensor and teeth of pulse wheel normal?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Visually inspect the CMP sensor and teeth of pulse wheel.

(See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZR-CD 2.2].)

Are the CMP sensor and teeth of pulse wheel normal?

Yes

Access the following PIDs using the M-MDS:

(See ON-BOARD DIAGNOSTIC TEST [MZR-CD 2.2].)

(See PCM INSPECTION [MZR-CD 2.2].)

• ECT

• IAT

• MAF

• MAP

• RPM

• VSS

― If the PID value is not normal:

• Repair or replace the malfunctioning part according to the inspection results.

― If the PID value is normal:

• Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Inspect the timing chain for the following:

• Chipping of gear teeth

• Low tension

• Breakage damage or cracks

Is there any malfunction?

Yes

If the valve timing is incorrect:

• Adjust the valve timing.

If the timing chain is not normal:

• Replace the timing chain.

(See TIMING CHAIN REMOVAL/INSTALLATION [MZR-CD 2.2].)

Inspect the following:

• Clutch slippage

• CKP sensor

• Boost sensor and related circuit

• Brake system for dragging

• Coolant heater system

• Glow system

― If there is any malfunction:

• Repair or replace the malfunctioning part according to the inspection results.

― If there is no malfunction:

• Remove the supply pump.

(See SUPPLY PUMP REMOVAL/INSTALLATION [MZR-CD 2.2].)

• Inspect the supply pump.

(See SUPPLY PUMP INSPECTION [MZR-CD 2.2].)

• Repair or replace the malfunctioning part according to the inspection results.

Verify test results.

• If normal, return to the diagnostic index to service any additional symptoms.

(See SYMPTOM DIAGNOSTIC INDEX [MZR-CD 2.2].)

• If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis.

― If the vehicle is repaired, troubleshooting is completed.

― If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.