NO.10 LOW IDLE/STALLS DURING DECELERATION [L8, LF]


id0103a0801600

10

LOW IDLE/STALLS DURING DECELERATION

DESCRIPTION

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

POSSIBLE CAUSE

• Vacuum leakage
• Improper operation of electronic throttle control system
• Air leakage from intake-air system
• Improper air/fuel mixture ratio control
• Evaporative emission control system malfunction
• Accelerator pedal position sensor or related circuit malfunction
• 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 (MT)
• TR switch or related circuit malfunction (AT)
• 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
• No air leakage from intake-air system
Are all items normal?
Yes
Go to the next step.
No
Service if necessary.
Repeat Step 3.
4
Connect the M-MDS to the DLC-2.
Retrieve any continuous memory, KOEO and KOER DTCs using M-MDS.
Are there any DTCs displayed?
Yes

DTC is displayed:

Go to the appropriate DTC inspection.
No

No DTC is displayed:

Go to the next step.
5
Inspect the electronic throttle control system operation.
Does the electronic throttle control system operate properly?
Yes
Go to the next step.
No
Repair or replace malfunctioning part according to inspection results.
6
Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side.
Plug opening 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 M-MDS to the DLC-2.
Access following PIDs.

PCM PID:

• APP1
• APP2
• TP
• MAF
• VSS
• BOO
• CPP (MT)
• CPP/PNP (MT)

TCM PID:

• TR (AT)
Monitor each PID while driving the vehicle.
Are PIDs normal?
Yes
Intermittent concern exists.
No

APP1, APP2 PIDs:

Inspect accelerator pedal position sensor.

TP PID:

Inspect the TP sensor.

MAF PID:

Inspect the MAF sensor.

VSS PID:

Inspect the VSS.

BOO PID:

Inspect the brake switch.

CPP PID: (MT)

Inspect the clutch pedal position switch.

CPP/PNP PID: (MT)

Inspect the neutral switch.

TR PID: (AT)

Inspect the TR switch.
8
Verify test results.
• If normal, return to diagnostic index to service any additional symptoms.
• If malfunction remains, inspect related Service information perform repair or diagnosis.
- If vehicle repaired, troubleshooting completed.
- If vehicle not repaired or additional diagnostic information not available, replace the PCM.
(See PCM REMOVAL/INSTALLATION [L8, LF].)