NO.10 LOW IDLE/STALLS DURING DECELERATION [WL-C, WE-C]

id0103b6801600

10

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
•  A/C system improper operation
•  Inadequate fuel pressure
•  Fuel pressure limiter malfunction (built-in common rail)
•  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 sensor/IAT sensor No.2 or related circuit malfunction
•  ECT sensor or related circuit malfunction
•  Fuel pressure sensor or related circuit malfunction
•  Accelerator pedal position (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 REPAIR PROCEDURE” and “AFTER REPAIR PROCEDURE” described in this manual.

Diagnostic Procedure

STEP

INSPECTION

RESULTS

ACTION
1
Does the engine idle roughly?
Yes
Go to the symptom troubleshooting “NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [WL-C, WE-C]”.
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 (Engine off).
Retrieve any DTCs.
Are any DTCs displayed?
Yes
DTC is displayed:
Go to the appropriate DTC test.
(See DTC TABLE [WL-C, WE-C (Thailand, General (L.H.D. R.H.D.) specs.)].)
Communication error message is displayed:
Inspect the following:
•  Open circuit between main relay and PCM terminal 201, 203, 205
•  Open circuit main relay and PCM terminal 219
•  Main relay stuck open
•  Open or poor ground circuit (PCM terminal 202, 204, 206)
•  Poor connection to vehicle body ground
No
No DTC is displayed:
Go to the next step.
4
Inspect idle speed.
(See ENGINE TUNE-UP [WL-C, WE-C].)
Is the idle speed correct?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the idle speed inspection results.
5
Inspect the APP sensor.
(See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [WL-C, WE-C].)
Is the APP sensor normal?
Yes
Go to the next step.
No
Replace the accelerator pedal component.
6
Inspect the CKP sensor.
(See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [WL-C, WE-C].)
(See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [WL-C, WE-C].)
Is the CKP sensor normal?
Yes
Go to the next step.
No
Replace the CKP sensor.
Then go to the next step.
7
Visually inspect the CMP sensor and the teeth of the pulse wheel.
Are the CMP sensor and the teeth of the pulse wheel normal?
Yes
Inspect the following PIDs:
(See PCM INSPECTION (Thailand, General (L.H.D. R.H.D.) specs.) [WL-C, WE-C].)
•  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.
8
Inspect the fuel pressure sensor.
(See FUEL PRESSURE SENSOR INSPECTION [WL-C, WE-C].)
Is the fuel pressure normal?
Yes
Go to the next step.
No
Replace the common rail.
9
Is the engine compression correct?
(See COMPRESSION INSPECTION [WL-C, WE-C].)
Yes
Go to the next step.
No
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.
10
Inspect fuel injector.
(See FUEL INJECTOR INSPECTION [WL-C, WE-C].)
Is fuel injector normal?
Yes
Go to the next step.
No
Repair or replace if necessary.
(See FUEL INJECTOR REMOVAL/INSTALLATION [WL-C, WE-C].)
11
Note
•  The following test should be performed on vehicles with an 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 an A/C system.
Connect the pressure gauge to A/C line.
Turn the blower and A/C switches on.
Is the pressure within specifications?
Yes
Go to the next step.
No
A/C is always on:
Go to the symptom troubleshooting “NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [WL-C, WE-C]”.
Other symptoms:
Inspect the following:
•  Refrigerant charging amount
•  Cooling fan operation
12
Inspect the EGR system operation.
Is the EGR system operation normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to EGR system operation results.
13
Inspect the glow system operation.
(See GLOW PLUG RELAY INSPECTION [WL-C, WE-C].)
Is glow system operation normal?
Yes
Remove and inspect the supply pump and common rail.
No
Service if necessary.
14
Verify test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If the malfunction remains, inspect the related Service Information and perform repair or diagnosis.
―  If the vehicle is repaired, troubleshooting completed.
―  If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if later calibration is available. Retest.