NO.4 ENGINE STALLS-AFTER START/AT IDLE [WL-3]

STEP	INSPECTION	ACTION
1	• Inspect for the following: ― Fuel quality including water contamination ― Fuel line restriction ― Loose bands on the intake-air system ― Cracks on the intake-air system parts ― Intake-air system restriction • Are all items normal?	Yes	Go to the next step.
No	Service if necessary. Repeat Step 1.
2	• Is the engine overheating?	Yes	Go to symptom troubleshooting “NO.13 COOLING SYSTEM CONCERNS-OVERHEATING.”
No	Go to the next step.
3	Note • Ignore DTC P0120 while performing this test. • Disconnect the APP sensor connector. • Measure the voltage at the APP sensor connector VREF terminal with the engine switch turned to the ON position. Specification 4.5—5.5 V • Is the voltage normal?	Yes	Go to the next step.
No	Go to symptom troubleshooting “NO.21 CONSTANT VOLTAGE.”
4	• Connect the M-MDS to the DLC. • Turn the engine switch to the ON position (Engine off). • Retrieve any DTCs. • Is a DTC displayed?	Yes	DTC is displayed: • Go to the appropriate DTC test. Communication error message is displayed: • Inspect for the following: ― Open circuit between main relay and PCM terminal 4C ― Open main relay ground circuit ― Main relay is stuck open ― Open PCM ground circuit (terminal 4A or 4B) ― Poor connection of vehicle body ground
No	No DTC is displayed: • Go to the next step.
5	• Does engine run normal after warm-up?	Yes	Go to the next step.
No	Go to Step 7.
6	• Inspect the glow plug and glow plug relay. (See GLOW PLUG INSPECTION [WL-3].) • Is the glow system operation normal?	Yes	Go to the next step.
No	Repair or replace any malfunctioning parts according to the glow system operation results.
7	• Access the RPM PID. • Is the RPM PID indicating the engine speed while the engine is during cranking?	Yes	Go to the next step.
No	Inspect for the following: • Open or short circuit in the fuel pump speed sensor • Open or short circuit in the fuel pump speed sensor wiring harnesses • Open or short circuit between the fuel pump speed sensor and PCM terminals 2K and 2D
8	Note • The following test should be performed on vehicles with the A/C system. If the following test cannot be performed due to engine stalls, 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 lines. • Turn the blower switch on. • Is the pressure within specification? (See REFRIGERANT PRESSURE CHECK.)	Yes	Go to the next step.
No	A/C is always on: • Go to symptom troubleshooting "NO.19 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY." Other symptoms: • Inspect the following: ― Refrigerant charging amount ― Cooling fan operation
9	• Depress the accelerator pedal slightly. • Crank the engine. • Does the engine start now?	Yes	Inspect and adjust the idle speed. (See ENGINE TUNE-UP [WL-3]) If the symptom still appears, go to the next step.
No	Go to the next step.
10	• Perform the fuel cut solenoid valve inspection. (See FUEL CUT SOLENOID VALVE INSPECTION [WL-3].) • Is the fuel cut solenoid valve normal?	Yes	Go to the next step.
No	Inspect for the following: • Stuck fuel cut solenoid valve • Open circuit in fuel cut solenoid valve • Poor ground of fuel cut solenoid valve • Open circuit between the fuel cut solenoid valve and the PCM connector terminal 4W Repair or replace any malfunctioning parts.
11	• Inspect for fuel leakage from the fuel pipe. • Is any fuel leakage found on the fuel pipe?	Yes	Repair or replace if necessary.
No	Go to the next step.
12	• Access the EGR PID. • Read the EGR PID while cranking the engine. (See PCM INSPECTION [WL-3]) • Is the EGR PID normal?	Yes	Go to the next step.
No	Inspect the following: • EGR solenoid valve (vent) • EGR solenoid valve (vacuum) • EGR valve • Vacuum hose connections • Wiring harness between EGR solenoid valve (vacuum) and PCM terminal 4T Repair or replace if necessary.
13	• Inspect the injection timing. • Is the injection timing normal?	Yes	Go to the next step.
No	Inspect the TCV. (See TIMER CONTROL VALVE (TCV) INSPECTION [WL-3].) If the TCV is normal, adjust the injection timing.
14	• Inspect the fuel filter for clogging. • Is the fuel filter normal?	Yes	Go to the next step.
No	Replace the fuel filter cartridge.
15	• Remove the injection nozzle. • Inspect the injection nozzle for the following: ― Clogged nozzle ― Seized needle valve ― Incorrect valve opening pressure ― Malfunctioning nozzle gasket • Is the injection nozzle normal?	Yes	Go to the next step.
No	Repair or replace the injection nozzle.
16	• Measure the engine compression. • Is the compression normal?	Yes	Go to Step 18.
No	Go to the next step.
17	• Inspect the timing belt for the following: ― Chipping of gear teeth ― Low tension ― Breakage, damage or cracks • Is the timing belt normal?	Yes	Inspect for the following: • Burnt valve • Worn piston, piston ring or cylinder • Damaged cylinder head gasket • Damaged valve seat • Worn valve seat or valve guide Repair or replace if necessary.
No	If the timing is incorrect, adjust the timing. If the timing belt is not normal, replace the timing belt.
18	• Is the valve clearance correct?	Yes	Inspect the following: • Idle switch • Neutral switch • Start signal (PCM terminal 1U) • MAF sensor/IAT sensor No.2 • IAT sensor No.1 • VSS • Fuel pump speed sensor If normal, remove and inspect the injection pump.
No	Adjust the valve clearance.
19	• Verify the test results. If normal, return to the diagnostic index to service any additional symptoms.

STEP

INSPECTION

ACTION

• Inspect for the following:

― Fuel quality including water contamination

― Fuel line restriction

― Loose bands on the intake-air system

― Cracks on the intake-air system parts

― Intake-air system restriction

• Are all items normal?

Yes

Go to the next step.

Service if necessary.

Repeat Step 1.

• Is the engine overheating?

Yes

Go to symptom troubleshooting “NO.13 COOLING SYSTEM CONCERNS-OVERHEATING.”

Go to the next step.

Note

• Ignore DTC P0120 while performing this test.

• Disconnect the APP sensor connector.

• Measure the voltage at the APP sensor connector VREF terminal with the engine switch turned to the ON position.

Specification

4.5—5.5 V

• Is the voltage normal?

Yes

Go to the next step.

Go to symptom troubleshooting “NO.21 CONSTANT VOLTAGE.”

• Connect the M-MDS to the DLC.

• Turn the engine switch to the ON position (Engine off).

• Retrieve any DTCs.

• Is a DTC displayed?

Yes

DTC is displayed:

• Go to the appropriate DTC test.

Communication error message is displayed:

• Inspect for the following:

― Open circuit between main relay and PCM terminal 4C

― Open main relay ground circuit

― Main relay is stuck open

― Open PCM ground circuit (terminal 4A or 4B)

― Poor connection of vehicle body ground

No DTC is displayed:

• Go to the next step.

• Does engine run normal after warm-up?

Yes

Go to the next step.

Go to Step 7.

• Inspect the glow plug and glow plug relay.

(See GLOW PLUG INSPECTION [WL-3].)

• Is the glow system operation normal?

Yes

Go to the next step.

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

• Access the RPM PID.

• Is the RPM PID indicating the engine speed while the engine is during cranking?

Yes

Go to the next step.

Inspect for the following:

• Open or short circuit in the fuel pump speed sensor

• Open or short circuit in the fuel pump speed sensor wiring harnesses

• Open or short circuit between the fuel pump speed sensor and PCM terminals 2K and 2D

Note

• The following test should be performed on vehicles with the A/C system. If the following test cannot be performed due to engine stalls, 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 lines.

• Turn the blower switch on.

• Is the pressure within specification?

(See REFRIGERANT PRESSURE CHECK.)

Yes

Go to the next step.

A/C is always on:

• Go to symptom troubleshooting "NO.19 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY."

Other symptoms:

• Inspect the following:

― Refrigerant charging amount

― Cooling fan operation

• Depress the accelerator pedal slightly.

• Crank the engine.

• Does the engine start now?

Yes

Inspect and adjust the idle speed.

(See ENGINE TUNE-UP [WL-3])

If the symptom still appears, go to the next step.

Go to the next step.

• Perform the fuel cut solenoid valve inspection.

(See FUEL CUT SOLENOID VALVE INSPECTION [WL-3].)

• Is the fuel cut solenoid valve normal?

Yes

Go to the next step.

Inspect for the following:

• Stuck fuel cut solenoid valve

• Open circuit in fuel cut solenoid valve

• Poor ground of fuel cut solenoid valve

• Open circuit between the fuel cut solenoid valve and the PCM connector terminal 4W

Repair or replace any malfunctioning parts.

• Inspect for fuel leakage from the fuel pipe.

• Is any fuel leakage found on the fuel pipe?

Yes

Repair or replace if necessary.

Go to the next step.

• Access the EGR PID.

• Read the EGR PID while cranking the engine.

(See PCM INSPECTION [WL-3])

• Is the EGR PID normal?

Yes

Go to the next step.

Inspect the following:

• EGR solenoid valve (vent)

• EGR solenoid valve (vacuum)

• EGR valve

• Vacuum hose connections

• Wiring harness between EGR solenoid valve (vacuum) and PCM terminal 4T

Repair or replace if necessary.

• Inspect the injection timing.

• Is the injection timing normal?

Yes

Go to the next step.

Inspect the TCV.

(See TIMER CONTROL VALVE (TCV) INSPECTION [WL-3].)

If the TCV is normal, adjust the injection timing.

• Inspect the fuel filter for clogging.

• Is the fuel filter normal?

Yes

Go to the next step.

Replace the fuel filter cartridge.

• Remove the injection nozzle.

• Inspect the injection nozzle for the following:

― Clogged nozzle

― Seized needle valve

― Incorrect valve opening pressure

― Malfunctioning nozzle gasket

• Is the injection nozzle normal?

Yes

Go to the next step.

Repair or replace the injection nozzle.

• Measure the engine compression.

• Is the compression normal?

Yes

Go to Step 18.

Go to the next step.

• Inspect the timing belt for the following:

― Chipping of gear teeth

― Low tension

― Breakage, damage or cracks

• Is the timing belt normal?

Yes

Inspect for the following:

• Burnt valve

• Worn piston, piston ring or cylinder

• Damaged cylinder head gasket

• Damaged valve seat

• Worn valve seat or valve guide

Repair or replace if necessary.

If the timing is incorrect, adjust the timing.

If the timing belt is not normal, replace the timing belt.

• Is the valve clearance correct?

Yes

Inspect the following:

• Idle switch

• Neutral switch

• Start signal (PCM terminal 1U)

• MAF sensor/IAT sensor No.2

• IAT sensor No.1

• VSS

• Fuel pump speed sensor

If normal, remove and inspect the injection pump.

Adjust the valve clearance.

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

4	Engine stalls—after start/at idle
DESCRIPTION	• Engine stops unexpectedly at idle and/or after starting.
POSSIBLE CAUSE	• Poor fuel quality • Intake-air system restriction • Incorrect idle speed • Engine overheating • A/C system improper operation • Fuel cut solenoid valve malfunction • Main relay malfunction • Glow system malfunction • Fuel leakage • Fuel line restriction • Fuel filter clogging • Incorrect fuel injection timing • Injection pump malfunction • Injection nozzle malfunction • Low engine compression • EGR system malfunction • MAF sensor/IAT sensor No.2 malfunction • IAT sensor No.1 malfunction • VSS malfunction