NO.10 LOW IDLE/STALLS DURING DECELERATION [MZI-3.7]

id0103d2801600

10 | LOW IDLE/STALLS DURING DECELERATION
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DESCRIPTION | • Engine stops unexpectedly at beginning of deceleration or recovery from deceleration.
POSSIBLE CAUSE | • Improper magnetic clutch operation • Vacuum leakage • Air leakage from intake-air system • Improper routing vacuum line • PCM DTC is stored. • Improper operation of drive-by-wire control system • EVAP control system malfunction • Erratic signal to PCM ― APP sensor or related circuit malfunction ― TP sensor or related circuit malfunction ― MAF sensor or related circuit malfunction ― Brake switch or related circuit malfunction ― TR switch or related circuit malfunction ― VSS or related circuit malfunction

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Does the engine idle roughly? | Yes | Go to the symptom troubleshooting “NO.8 ENGINE RUNS ROUGH/ROLLING IDLE”. (See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [MZI-3.7].)
No | Go to the next step.
2 | Turn off the A/C switch and fan switch. Does the magnetic clutch engage? | Yes | Go to the symptom troubleshooting “NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY.“ (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7].)
No | Go to the next step.
3 | Verify the following: • Proper routing of and no damage to vacuum lines • No air leakage from intake-air system Are all items normal? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results. Repeat Step 3.
4 | Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) Are there any DTCs displayed? | Yes | DTC is displayed: • Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7].)
No | No DTC is displayed: • Go to the next step.
5 | Perform the drive-by-wire control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].) Does the drive-by-wire control system function properly? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results.
6 | Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Start the engine. Is the engine stall now eliminated? | Yes | Inspect the EVAP control system. Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
7 | Caution • While performing this step, always operate the vehicle in a safe and lawful manner. • When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs and VSS using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) • APP1 • APP2 • TP1 • TP2 • MAF • VSS Monitor each PID while driving the vehicle. Are all PIDs normal? (See PCM INSPECTION [MZI-3.7].) | Yes | Go to the next step.
No | APP1, APP2 PID is not normal: • Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI-3.7].) TP1 or TP2 PID is not normal: • Inspect the TP sensor. (See THROTTLE POSITION (TP) SENSOR INSPECTION [MZI-3.7].) MAF PID is not normal: • Inspect the MAF sensor. (See MASS AIR FLOW (MAF) SENSOR INSPECTION [MZI-3.7].) VSS PID is not normal: • Inspect the VSS. (See VEHICLE SPEED SENSOR (VSS) INSPECTION [AY6A-EL, AY6AX-EL].) Repair or replace the malfunctioning part according to the inspection results.
8 | Access and monitor the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) • AC_REQ • BOO • TR Are all PIDs normal? (See PCM INSPECTION [MZI-3.7].) | Yes | Go to the next step.
No | AC_REQ PID is not normal: • Inspect the followings: ― Refrigerant pressure sensor ― Front climate control unit terminal 2A voltage ― Wiring harness between front climate control unit terminal 2A and instrument cluster terminal 1C BOO PID is not normal: • Inspect the brake switch, and related wiring harness for vibration or intermittent open/short circuit. TR PID is not normal: • Inspect the TR switch and related wiring harness for vibration or intermittent open/short circuit. Repair or replace the malfunctioning part according to the inspection results.
9 | • Verify test results. ― If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].) ― If malfunction remains, inspect related Service Information and perform repair or diagnosis. • If vehicle is repaired, troubleshooting completed. • If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7].)