NO.10 LOW IDLE/STALLS DURING DECELERATION [L3 R.H.D.]


id0103a4801600

10

LOW IDLE/STALLS DURING DECELERATION

DESCRIPTION

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

POSSIBLE CAUSE

• Vacuum leakage
• IAC valve malfunction
• Air leakage from intake-air system
• Improper air/fuel mixture ratio control
• Evaporative emission control system malfunction
• TP sensor misadjustment
• TP sensor or related circuit malfunction
• MAF sensor or related circuit malfunction
• Brake switch or related circuit malfunction
• Neutral/clutch pedal position switch or related circuit malfunction (MTX)
• TR switch or related circuit malfunction (ATX)
• Improper A/C magnetic clutch operation

Diagnostic procedure

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
Turn off the A/C switch and fan switch.
Does the A/C magnetic clutch engage?
Yes
Go to symptom troubleshooting "No.24 A/C is always on or A/C compressor runs continuously."
No
Go to the next step.
3
Verify the following:
• Proper routing and no damage of vacuum lines
• IAC valve is connected properly.
• No air leakage from intake-air system
Are all items normal?
Yes
Go to the next step.
No
Repair or replace if necessary.
Repeat Step 3.
4
Connect the WDS or equivalent to the DLC-2.
Retrieve any continuous memory, KOEO and KOER DTCs using the WDS or equivalent.
Are any DTCs displayed?
Yes

DTC is displayed:

Go to the appropriate DTC inspection.
No

No DTC is displayed:

Go to the next step.
5
Does the idle speed drop or stall when the IAC valve is disconnected?
Yes
Go to the next step.
No
Inspect the following:
• Circuit from IAC valve to the PCM terminal 88 or 89 for open or short
• IAC valve for sticking
If normal, go to the next step.
6
Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side.
Plug the opened end of vacuum hose.
Drive vehicle.
Does engine condition improve?
Yes
Inspect the evaporative emission control system.
No
Go to the next step.
7
Connect the WDS or equivalent to the DLC-2.
Access the TP, MAF, VSS, BOO, CPP and PNP, PIDs.
Monitor each PID while driving the vehicle.
Are the PIDs normal?
Yes
Intermittent concern exists.
No

TP PID:

Inspect the TP sensor.

MAF PID:

Inspect the MAF sensor.

VSS PID:

Inspect the VSS.

BOO PID:

Inspect the brake switch.

TR PID:

Inspect the TR switch.
8
Verify test results.
• If normal, return to the diagnostic index to service any additional symptoms.
• If any malfunction remains, inspect related service information, and 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 [L3].)