NO.10 LOW IDLE/STALLS DURING DECELERATION [MZR 1.8, MZR 2.0, MZR 2.5]


id0103d4801600

10

LOW IDLE/STALLS DURING DECELERATION

DESCRIPTION
•  Engine stops unexpectedly at beginning of deceleration or recovery from deceleration.
POSSIBLE CAUSE
•  ECT sensor malfunction
•  Improper operation of A/C magnetic clutch
•  Vacuum leakage
•  Air leakage from intake air system
•  PCM DTC is stored
•  Improper operation of electronic throttle control system
•  Improper operation of evaporative emission control system
•  Erratic signal to PCM
―  APP sensor malfunction
―  Brake switch malfunction
―  TP sensor malfunction
―  MAF sensor malfunction
―  VSS malfunction
•  Improper load signal input
―  Refrigerant pressure switch malfunction
―  Evaporator temperature sensor malfunction
―  Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal)
―  CPP switch malfunction (MTX)
―  Neutral switch malfunction (MTX)
―  TR switch malfunction (ATX)
―  Communication error between TCM and PCM (ATX)

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”.
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 the symptom troubleshooting “NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY.“
No
Go to the next step.
3
Inspect the following:
•  Proper routing of and no damage to the vacuum lines
•  No air leakage from the intake air system
Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
4
Perform the PCM DTC inspection using the M-MDS.
Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
Go to the next step.
5
Perform the Electronic Throttle Control System Inspection.
Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
6
Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side.
Plug the open end of the vacuum hose.
Drive the vehicle.
Does the engine condition improve?
Yes
Inspect the evaporative emission 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 PIDs using the M-MDS:
•  APP1
•  APP2
•  BOO
•  TP1
•  TP2
•  MAF
•  VSS
Do the PIDs indicate the correct values under the trouble condition?
Yes
Go to the next step.
No
APP1, APP2 PIDs are not specified:
BOO PID is not specified:
•  Inspect the brake switch.
TP1, TP2 PIDs are not specified:
MAF PID is not specified:
VSS PID is not specified:
Repair or replace the malfunctioning part according to the inspection results.
8
Access the following PIDs using the M-MDS:
•  AC_REQ
•  COLP
•  CPP (MTX)
•  CPP/PNP (MTX)
•  TR (ATX)
Are the PID values normal?
Yes
Go to the next step.
No
AC_REQ PID is not specified:
COLP PID is not specified:
CPP PID is not specified: (MTX)
CPP/PNP PID is not specified: (MTX)
•  Inspect the neutral switch.
TR PID is not specified: (ATX)
•  Inspect the TR switch.
•  Inspect communication error between TCM and PCM.
Repair or replace the malfunctioning part according to the inspection results.
9
Verify test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis.
―  If the vehicle is repaired, troubleshooting is completed.
―  If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.