NO.12 LOW IDLE/STALLS DURING DECELERATION [MZR-CD 2.2]

12	LOW IDLE/STALLS DURING DECELERATION
DESCRIPTION	• Engine stops unexpectedly at the beginning of deceleration or recovery from deceleration.
POSSIBLE CAUSE	• Intake-air system restriction or clogging • Poor fuel quality • Improper operation of A/C system • Inadequate fuel pressure ― Fuel pressure sensor or related circuit malfunction ― Fuel pressure limiter malfunction (built-in common rail) ― Suction control valve control circuit malfunction (damaged to driver in PCM caused by short circuit to ground system) ― Suction control valve malfunction (built-in supply pump) ― Supply pump malfunction • Fuel leakage • Fuel line restriction or clogging • Fuel filter restriction or clogging • Incorrect fuel injection timing • Incorrect idle speed • Erratic signal from CKP sensor • Erratic signal from CMP sensor • Fuel injector malfunction • Low engine compression • Improper valve timing • Glow system malfunction • Fuel warmer malfunction • EGR system malfunction • MAF/IAT sensor or related circuit malfunction • ECT sensor or related circuit malfunction • Neutral switch malfunction or related circuit malfunction • APP sensor or related circuit malfunction 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].)

LOW IDLE/STALLS DURING DECELERATION

DESCRIPTION

• Engine stops unexpectedly at the beginning of deceleration or recovery from deceleration.

POSSIBLE CAUSE

• Intake-air system restriction or clogging

• Poor fuel quality

• Improper operation of A/C system

• Inadequate fuel pressure

― Fuel pressure sensor or related circuit malfunction

― Fuel pressure limiter malfunction (built-in common rail)

― Suction control valve control circuit malfunction (damaged to driver in PCM caused by short circuit to ground system)

― Suction control valve malfunction (built-in supply pump)

― Supply pump malfunction

• Fuel leakage

• Fuel line restriction or clogging

• Fuel filter restriction or clogging

• Incorrect fuel injection timing

• Incorrect idle speed

• Erratic signal from CKP sensor

• Erratic signal from CMP sensor

• Fuel injector malfunction

• Low engine compression

• Improper valve timing

• Glow system malfunction

• Fuel warmer malfunction

• EGR system malfunction

• MAF/IAT sensor or related circuit malfunction

• ECT sensor or related circuit malfunction

• Neutral switch malfunction or related circuit malfunction

• APP sensor or related circuit malfunction

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	Does the engine idle roughly?	Yes	Go to the symptom troubleshooting “NO.10 ENGINE RUNS ROUGH/ROLLING IDLE”. (See NO.10 ENGINE RUNS ROUGH/ROLLING IDLE [MZR-CD 2.2].)
No	Go to the next step.
2	Inspect the following: • Fuel line/fuel filter clogging or restriction • Intake-air system restriction or clogging • Fuel quality (e.g.: include water contamination, winter/summer blend) Are all items normal?	Yes	Go to the next step.
No	Service if necessary. Repeat Step 2.
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	Inspect the idle speed. (See ENGINE TUNE-UP [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.
5	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.
6	Switch the ignition to ON (engine off). Measure the voltage at the following terminals (wiring harness-side): • PCM sensor terminal 2AL • PCM sensor terminal 2AT Is the voltage normal? (See PCM INSPECTION [MZR-CD 2.2].)	Yes	Go to the next step.
No	If the PCM terminal 2AL voltage is not normal: • Inspect the CPP switch and related wiring harness. (See CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION [MZR-CD 2.2].) If the PCM terminal 2AT voltage is not normal: • Inspect the neutral switch and related wiring harness. (See NEUTRAL SWITCH INSPECTION [MZR-CD 2.2].) Repair or replace the malfunctioning part according to the inspection results.
7	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.
8	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 • RPM ― 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.
9	Inspect the suction control valve. (See SUCTION CONTROL VALVE INSPECTION [MZR-CD 2.2].) Is there any malfunction?	Yes	Replace the supply pump. (See SUPPLY PUMP REMOVAL/INSTALLATION [MZR-CD 2.2].)
No	Go to the next step.
10	Switch the ignition to off. Disconnect the suction control valve and PCM connectors. Inspect for continuity between suction control valve terminal A (wiring harness-side) and body ground. Is there continuity?	Yes	Repair or replace the wiring harness for a possible short to ground. • If the malfunction remains: ― Replace the PCM. (damaged to driver in PCM caused by short circuit to ground system) (See PCM REMOVAL/INSTALLATION [MZR-CD 2.2].)
No	Go to the next step.
11	Inspect the fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION [MZR-CD 2.2].) Is there any malfunction?	Yes	Replace the common rail. (See COMMON RAIL REMOVAL/INSTALLATION [MZR-CD 2.2].)
No	Go to the next step.
12	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.
13	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.
14	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.
15	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.
16	Inspect the fuel warmer. (See FUEL WARMER INSPECTION [MZR-CD 2.2].) Is there any malfunction?	Yes	Replace the fuel warmer. (See FUEL FILTER COMPONENT DISASSEMBLY/ASSEMBLY [MZR-CD 2.2].)
No	Go to the next step.
17	Inspect the glow system operation. (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	Remove the supply pump and common rail. (See SUPPLY PUMP REMOVAL/INSTALLATION [MZR-CD 2.2].) (See COMMON RAIL REMOVAL/INSTALLATION [MZR-CD 2.2].) Inspect the supply pump and common rail. (See SUPPLY PUMP INSPECTION [MZR-CD 2.2].) (See COMMON RAIL 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

Does the engine idle roughly?

Yes

Go to the symptom troubleshooting “NO.10 ENGINE RUNS ROUGH/ROLLING IDLE”.

(See NO.10 ENGINE RUNS ROUGH/ROLLING IDLE [MZR-CD 2.2].)

Go to the next step.

Inspect the following:

• Fuel line/fuel filter clogging or restriction

• Intake-air system restriction or clogging

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

Are all items normal?

Yes

Go to the next step.

Service if necessary.

Repeat Step 2.

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.

Inspect the idle speed.

(See ENGINE TUNE-UP [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.

Switch the ignition to ON (engine off).

Measure the voltage at the following terminals (wiring harness-side):

• PCM sensor terminal 2AL

• PCM sensor terminal 2AT

Is the voltage normal?

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

Yes

Go to the next step.

If the PCM terminal 2AL voltage is not normal:

• Inspect the CPP switch and related wiring harness.

(See CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION [MZR-CD 2.2].)

If the PCM terminal 2AT voltage is not normal:

• Inspect the neutral switch and related wiring harness.

(See NEUTRAL SWITCH INSPECTION [MZR-CD 2.2].)

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

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

• RPM

― 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 suction control valve.

(See SUCTION CONTROL VALVE INSPECTION [MZR-CD 2.2].)

Is there any malfunction?

Yes

Replace the supply pump.

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

Go to the next step.

Switch the ignition to off.

Disconnect the suction control valve and PCM connectors.

Inspect for continuity between suction control valve terminal A (wiring harness-side) and body ground.

Is there continuity?

Yes

Repair or replace the wiring harness for a possible short to ground.

• If the malfunction remains:

― Replace the PCM. (damaged to driver in PCM caused by short circuit to ground system)

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

Go to the next step.

Inspect the fuel pressure sensor.

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

Is there any malfunction?

Yes

Replace the common rail.

(See COMMON RAIL 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.

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.

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 fuel warmer.

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

Is there any malfunction?

Yes

Replace the fuel warmer.

(See FUEL FILTER COMPONENT DISASSEMBLY/ASSEMBLY [MZR-CD 2.2].)

Go to the next step.

Inspect the glow system operation.

(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.

Remove the supply pump and common rail.

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

(See COMMON RAIL REMOVAL/INSTALLATION [MZR-CD 2.2].)

Inspect the supply pump and common rail.

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

(See COMMON RAIL 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.