NO.10 LOW IDLE/STALLS DURING DECELERATION [MZ-CD 1.6 (Y6)]

10	LOW IDLE/STALLS DURING DECELERATION
DESCRIPTION	• The engine stops unexpectedly at the beginning of deceleration or recovery from deceleration.
POSSIBLE CAUSE	• Intake-air system restriction or clogging • Poor fuel quality • A/C system improper operation • Inadequate fuel pressure • Fuel metering valve malfunction • Fuel pressure limiter 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 • Supply pump malfunction • Fuel injector malfunction • Low engine compression • Improper valve timing • Glow system malfunction • EGR system malfunction • MAF/IAT sensor or related circuit malfunction • ECT sensor or related circuit malfunction • Fuel pressure sensor or related circuit malfunction • Clutch pedal position switch malfunction or related circuit malfunction • Accelerator pedal position sensor or related circuit malfunction • Idle switch or related circuit malfunction Предупреждение The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system: • 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 REPAIR PROCEDURE” and “AFTER REPAIR PROCEDURE” described in this manual.

LOW IDLE/STALLS DURING DECELERATION

DESCRIPTION

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

POSSIBLE CAUSE

• Intake-air system restriction or clogging

• Poor fuel quality

• A/C system improper operation

• Inadequate fuel pressure

• Fuel metering valve malfunction

• Fuel pressure limiter 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

• Supply pump malfunction

• Fuel injector malfunction

• Low engine compression

• Improper valve timing

• Glow system malfunction

• EGR system malfunction

• MAF/IAT sensor or related circuit malfunction

• ECT sensor or related circuit malfunction

• Fuel pressure sensor or related circuit malfunction

• Clutch pedal position switch malfunction or related circuit malfunction

• Accelerator pedal position sensor or related circuit malfunction

• Idle switch or related circuit malfunction

Предупреждение

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

• 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 REPAIR PROCEDURE” and “AFTER REPAIR PROCEDURE” described in this manual.

STEP	INSPECTION	RESULTS	ACTION
1	Does the engine idle rough?	Yes	Go to symptom troubleshooting “NO.8 ENGINE RUNS ROUGH/ROLLING IDLE”.
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 self-test function using the M-MDS. Turn the engine switch to the ON position. Retrieve any DTC. Are DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC test. Communication error message is displayed: Inspect for the following: • Open circuit between PCM control relay and PCM terminal 236, 231 • Open circuit between PCM control relay and PCM terminal 241 • PCM control relay stuck open • Open or poor ground circuit (PCM terminal 307, 308 or 332) • Poorly connected vehicle body ground
No	No DTC is displayed: Go to the next step.
4	Inspect idle speed. Is the idle speed correct?	Yes	Go to the next step.
No	Repair or replace malfunctioning parts according to the idle speed inspection results.
5	Connect the M-MDS to the DLC-2. Access the following PID. • APP Verify that the PID value when the accelerator pedal is depressed and/or released. Is the PID value normal?	Yes	Go to the next step.
No	Inspect and repair or replace the following part: • Accelerator pedal position sensor
6	Inspect the clutch pedal position switch. (See CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION [MZ-CD 1.6 (Y6)].) Is the clutch pedal position switch normal?	Yes	Go to the next step.
No	Replace the clutch pedal position switch.
7	Visually inspect CKP sensor and teeth of pulse wheel. Are the CKP sensor and the teeth of the pulse wheel normal?	Yes	Go to the next step.
No	Replace malfunctioning parts.
8	Measure gap between CKP sensor and teeth of pulse wheel. Specification 1.5—2.5 mm {0.059—0.098 in} Is the gap within the specification?	Yes	Go to the next step.
No	Adjust the CKP sensor position.
9	Visually inspect CMP sensor and teeth of pulse wheel. Are the CMP sensor and the teeth of the pulse wheel normal?	Yes	Inspect the following PIDs: (See PCM INSPECTION [MZ-CD 1.6 (Y6)].) • ECT • IAT • MAF • RPM If the PID value is not as specified, repair or replace malfunctioning parts. If the PID value is normal, go to the next step.
No	Replace malfunctioning parts.
10	Inspect fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION [MZ-CD 1.6 (Y6)].) Is the fuel pressure normal?	Yes	Go to the next step.
No	Replace the common rail.
11	Inspect fuel metering valve. (See ПРОВЕРКА ДОЗИРУЮЩЕГО КЛАПАНА [MZ-CD 1.6 (Y6)].) Is the fuel metering valve normal?	Yes	Go to the next step.
No	Replace the fuel pump. (See СНЯТИЕ И УСТАНОВКА ТНВД [MZ-CD 1.6 (Y6)].)
12	Is the engine compression correct?	Yes	Go to the next step.
No	Inspect for 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.
13	Inspect fuel injector. (See ПРОВЕРКА ТОПЛИВНЫХ ФОРСУНОК [MZ-CD 1.6 (Y6)].) Is fuel injector normal?	Yes	Go to the next step.
No	Repair or replace if necessary.
14	Примечание • The following test should be performed on vehicles with the A/C system. If the following test cannot be performed due to engine stalling, go to the next step. • Go to the next step for vehicles without the A/C system. Connect the pressure gauge to the A/C line. Turn the blower and the A/C switches on. Is the pressure within the specification?	Yes	Go to the next step.
No	A/C is always on: Go to symptom troubleshooting “NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”. Other symptoms: Inspect the following: • Refrigerant charging amount • Cooling fan operation
15	Inspect EGR system operation. Is the EGR system operation normal?	Yes	Go to the next step.
No	Repair or replace malfunctioning parts according to the EGR system operation results.
16	Inspect glow system operation. Is the glow system operation normal?	Yes	Remove and inspect the supply pump and common rail.
No	Service if necessary.
17	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZ-CD 1.6 (Y6)].) • If the malfunction remains, inspect related Service Information and perform repair or diagnosis. ― If the vehicle is repaired, troubleshooting is completed. ― If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZ-CD 1.6 (Y6)].)

STEP

INSPECTION

RESULTS

ACTION

Does the engine idle rough?

Yes

Go to symptom troubleshooting “NO.8 ENGINE RUNS ROUGH/ROLLING IDLE”.

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 self-test function using the M-MDS.

Turn the engine switch to the ON position.

Retrieve any DTC.

Are DTCs displayed?

Yes

DTC is displayed:

Go to the appropriate DTC test.

Communication error message is displayed:

Inspect for the following:

• Open circuit between PCM control relay and PCM terminal 236, 231

• Open circuit between PCM control relay and PCM terminal 241

• PCM control relay stuck open

• Open or poor ground circuit (PCM terminal 307, 308 or 332)

• Poorly connected vehicle body ground

No DTC is displayed:

Go to the next step.

Inspect idle speed.

Is the idle speed correct?

Yes

Go to the next step.

Repair or replace malfunctioning parts according to the idle speed inspection results.

Connect the M-MDS to the DLC-2.

Access the following PID.

• APP

Verify that the PID value when the accelerator pedal is depressed and/or released.

Is the PID value normal?

Yes

Go to the next step.

Inspect and repair or replace the following part:

• Accelerator pedal position sensor

Inspect the clutch pedal position switch.

(See CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION [MZ-CD 1.6 (Y6)].)

Is the clutch pedal position switch normal?

Yes

Go to the next step.

Replace the clutch pedal position switch.

Visually inspect CKP sensor and teeth of pulse wheel.

Are the CKP sensor and the teeth of the pulse wheel normal?

Yes

Go to the next step.

Replace malfunctioning parts.

Measure gap between CKP sensor and teeth of pulse wheel.

Specification

1.5—2.5 mm {0.059—0.098 in}

Is the gap within the specification?

Yes

Go to the next step.

Adjust the CKP sensor position.

Visually inspect CMP sensor and teeth of pulse wheel.

Are the CMP sensor and the teeth of the pulse wheel normal?

Yes

Inspect the following PIDs:

(See PCM INSPECTION [MZ-CD 1.6 (Y6)].)

• ECT

• IAT

• MAF

• RPM

If the PID value is not as specified, repair or replace malfunctioning parts.

If the PID value is normal, go to the next step.

Replace malfunctioning parts.

Inspect fuel pressure sensor.

(See FUEL PRESSURE SENSOR INSPECTION [MZ-CD 1.6 (Y6)].)

Is the fuel pressure normal?

Yes

Go to the next step.

Replace the common rail.

Inspect fuel metering valve.

(See ПРОВЕРКА ДОЗИРУЮЩЕГО КЛАПАНА [MZ-CD 1.6 (Y6)].)

Is the fuel metering valve normal?

Yes

Go to the next step.

Replace the fuel pump.

(See СНЯТИЕ И УСТАНОВКА ТНВД [MZ-CD 1.6 (Y6)].)

Is the engine compression correct?

Yes

Go to the next step.

Inspect for 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.

Inspect fuel injector.

(See ПРОВЕРКА ТОПЛИВНЫХ ФОРСУНОК [MZ-CD 1.6 (Y6)].)

Is fuel injector normal?

Yes

Go to the next step.

Repair or replace if necessary.

Примечание

• The following test should be performed on vehicles with the A/C system. If the following test cannot be performed due to engine stalling, go to the next step.

• Go to the next step for vehicles without the A/C system.

Connect the pressure gauge to the A/C line.

Turn the blower and the A/C switches on.

Is the pressure within the specification?

Yes

Go to the next step.

A/C is always on:

Go to symptom troubleshooting “NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”.

Other symptoms:

Inspect the following:

• Refrigerant charging amount

• Cooling fan operation

Inspect EGR system operation.

Is the EGR system operation normal?

Yes

Go to the next step.

Repair or replace malfunctioning parts according to the EGR system operation results.

Inspect glow system operation.

Is the glow system operation normal?

Yes

Remove and inspect the supply pump and common rail.

Service if necessary.

Verify test results.

• If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZ-CD 1.6 (Y6)].)

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

― If the vehicle is repaired, troubleshooting is completed.

― If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZ-CD 1.6 (Y6)].)