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

BME010300000W12

10 | LOW IDLE/STALLS DURING DECELERATION
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DESCRIPTION | • Engine stops unexpectedly at 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 switch or related circuit malfunction
• Improper A/C magnetic clutch operation

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | • Does engine idle rough? | Yes | Go to symptom troubleshooting "No.8 Engine runs rough/rolling idle".
No | Go to next step.
2 | Turn off A/C switch and fan switch. Does A/C magnetic clutch engauge? | Yes | Go to symptom troubleshooting "No.24 A/C is always on or A/C compressor runs continuously."
No | Go to next step.
3 | Verify following: • Proper routing and no damage of vacuum lines • IAC valve is connected properly. • No air leakage from intake-air system Are all items okay? | Yes | Go to next step.
No | Service as necessary. Repeat Step 3.
4 | Connect WDS or equivalent to DLC-2. Retrieve any continuous memory, KOEO and KOER DTCs. Are there any DTCs displayed? | Yes | DTC is displayed: Go to appropriate DTC test.
No | No DTC is displayed: Go to next step.
5 | Does idle speed drop or stall when disconnecting IAC valve? | Yes | Go to next step.
No | Inspect following: • Circuit from IAC valve to PCM connector terminal 4G or 4J for open and short • IAC valve for sticking If okay, go to next step.
6 | Disconnect vacuum hose between purge solenoid valve and intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Drive vehicle. Does engine condition improve? | Yes | Inspect evaporative emission control system.
No | Go to next step.
7 | Connect WDS or equivalent to DLC-2. Access TP, MAF, VSS, BOO, CPP and CPP/PNP PIDs. Monitor each PID while driving vehicle. (See PCM INSPECTION [L3].) Are PIDs okay? | Yes | Intermittent concern exists. (See INTERMITTENT CONCERN TROUBLESHOOTING [L3].)
No | TP PID: Inspect TP sensor. MAF PID: Inspect MAF sensor. VSS PID: Inspect VSS. BOO PID: Inspect brake switch. CPP PID: Inspect clutch switch.

CPP/PNP PID: Inspect neutral switch.

8 | Verify test results. • If okay, return to diagnostic index to service any additional symptoms. • If malfunction remains, replace PCM.