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

id0103d2801600

10

LOW IDLE/STALLS DURING DECELERATION
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
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.
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.
TP1 or TP2 PID is not normal:
•  Inspect the TP sensor.
MAF PID is not normal:
•  Inspect the MAF sensor.
VSS PID is not normal:
•  Inspect the VSS.
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.
―  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.