NO.10 LOW IDLE/STALLS DURING DECELERATION [13B-MSP]

id0103f2801600

10

LOW IDLE/STALLS DURING DECELERATION
DESCRIPTION
•  The engine stops unexpectedly at the beginning of deceleration or recovery from deceleration.
POSSIBLE CAUSE
•  Vacuum leakage
•  Air leakage from intake-air system
•  Air suction at intake-air system (between MAF sensor and intake part)
•  Improper operation of drive-by-wire control system (abnormal accelerator position and TP signals to PCM)
•  Drive-by-wire control system operates in fail-safe mode (abnormal accelerator position and TP signal to PCM)
•  Throttle body malfunction (restriction, stuck closed)
•  Evaporative emission control system malfunction
•  Improper operation of fuel cut control
•  Fuel injector improper operation
•  Fuel injector malfunction (leakage, clogging, improper injection amount)
•  Inadequate fuel pressure
•  Pressure regulator (integrated in fuel pump unit)
•  Fuel pump mechanical malfunction
•  Fuel line restriction or clogging
•  MAF sensor improper installation
•  MAF sensor or related circuit malfunction (abnormal signal to PCM)
•  Brake switch or related circuit malfunction (abnormal signal to PCM)
•  Neutral/CPP switch or related circuit malfunction (abnormal signal to PCM)
•  TR switch or related circuit malfunction (abnormal signal to PCM)
•  Low engine compression
―  Engine internal malfunction
―  Abnormal engine oil condition (viscosity, deterioration)
―  Low oil pressure
―  Excessive fuel pressure
―  Air mixed in oil line
―  Metering oil pump malfunction
•  Leakage or clogging in oil pipe
•  Leakage or clogging in oil nozzle
•  Improper A/C magnetic clutch malfunction
•  Misfire
•  Improper operation of torque converter clutch control (AT)
•  Loose installation of engine mounts
Warning
The following troubleshooting flow chart contains fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system:
•  Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.
•  Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE REPAIR PROCEDURE” and “AFTER REPAIR PROCEDURE” described in this manual.
Caution
•  Disconnecting/connecting quick release connector without cleaning it may possibly cause damage to fuel pipe and quick release connector. Always clean quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

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 [13B-MSP].)
No
Go to the next step.
2
Turn off the A/C switch and the 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.“
(See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [13B-MSP].)
No
Go to the next step.
3
Does the engine knock/ping/detonate?
Yes
Go to the symptom troubleshooting “No.13 Knocking/pinging/detonation-Acceleration/cruise”.
(See NO.13 KNOCKING/PINGING/DETONATION-ACCELERATION/CRUISE [13B-MSP].)
No
Go to the next step.
4
Verify the following:
•  Proper routing of and no damage to vacuum lines
•  No air leakage from intake-air system
•  Engine mount installation condition (loose)
Are all the items normal?
Yes
Go to the next step.
No
Service if necessary.
Repeat Step 4.
5
Connect the M-MDS to the DLC-2.
Turn the ignition switch to the ON position (Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [13B-MSP].)
No
Go to the next step.
6
Perform the drive-by-wire control system operation inspection.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [13B-MSP].)
Does the drive-by-wire control system work properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the drive-by-wire control system operation inspection results.
7
Disconnect the vacuum hose between the purge solenoid valve and the intake manifold at quick release connector.
Plug the opening end of the vacuum hose.
Drive the vehicle.
Does the engine condition improve?
Yes
Inspect evaporative emission control system.
No
Go to the next step.
8
Connect the M-MDS to the DLC-2.
Access APP1, APP2, TP_REL, MAF and VSS PIDs.
Monitor each PID while driving vehicle.
(See PCM INSPECTION [13B-MSP].)
Are the PIDs normal?
Yes
Go to the next step.
No
If the APP1, APP2 PIDs are not as specified: Inspect the APP sensor.
(See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [13B-MSP].)
If the TP_REL PID is not as specified: Inspect the TP sensor.
(See THROTTLE POSITION (TP) SENSOR INSPECTION [13B-MSP].)
If the MAF PID is not as specified: Inspect the MAF sensor.
(See MASS AIR FLOW (MAF) SENSOR INSPECTION [13B-MSP].)
If the VSS PID is not as specified: Inspect the DSC HU/CM.
(See ON-BOARD DIAGNOSIS [DYNAMIC STABILITY CONTROL (DSC)].)
9
Access and monitor BOO, CPP (MT), CPP/PNP (MT), and PNP_TCM (AT) PIDs.
Are PIDs values normal?
(See PCM INSPECTION [13B-MSP].)
(See PID/DATA MONITOR INSPECTION [SJ6A-EL].)
Yes
Go to the next step.
No
If the BOO PID is not normal:
Inspect brake switch, and related wiring harness for vibration or intermittent open/short circuit.
If the CPP PID is not normal:
Inspect clutch position switch and related wiring harness for vibration or intermittent open/short circuit.
If the CPP/PNP PID is not normal:
Inspect neutral position switch and related wiring harness for vibration or intermittent open/short circuit.
If the PNP_TCM PID is not normal:
Inspect the TR switch and related wiring harness for vibration or intermittent open/short circuit.
10
Inspect the fuel line pressure.
(SeeFUEL LINE PRESSURE INSPECTION [13B-MSP].)
Is the fuel line pressure correct?
Yes
Go to the next step.
No
Zero or low:
Inspect for clogged fuel line.
If normal, replace the fuel pump unit.
(See FUEL PUMP UNIT REMOVAL/INSTALLATION [13B-MSP].)
High:
Replace the fuel pump unit.
(See FUEL PUMP UNIT REMOVAL/INSTALLATION [13B-MSP].)
11
Perform the fuel injector operation inspection.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [13B-MSP].)
Are the fuel injectors operating properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning parts, according to the fuel injector operation inspection results.
12
Inspect the engine compression.
(See COMPRESSION INSPECTION [13B-MSP].)
Is it normal?
Yes
Go to step 18.
No
Go to the next step.
13
Perform the metering oil pump control inspection.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [13B-MSP].)
Does the metering oil pump control operate properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to inspection results.
After that overhaul or replace the engine.
14
Check the engine oil condition.
Is engine oil low viscosity and/or is there a gasoline odor?
Yes
Replace the engine oil.
After that overhaul or replace the engine.
No
Go to the next step.
15
Inspect the oil pressure.
(See OIL PRESSURE INSPECTION [13B-MSP].)
Is the oil pressure within the specification?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
After that overhaul or replace the engine.
16
Turn the ignition switch off.
Disconnect the fuel line quick release connector and install the fuel gauge to the fuel line.
Start the engine and run it at idle.
Measure the fuel line pressure at idle.
Is the fuel line pressure correct at idle?
(See FUEL LINE PRESSURE INSPECTION [13B-MSP].)
Yes
Go to the next step.
No
Replace the fuel pump unit.
(See FUEL PUMP UNIT REMOVAL/INSTALLATION [13B-MSP].)
After that overhaul or replace the engine.
17
Check the oil pipe between the metering oil pump and the metering oil nozzle.
Is there air and/or clogging in oil pipe?
Yes
Inspect and repair for leakage and/or clogging in the oil passage at engine.
After that overhaul or replace the engine.
No
Overhaul or replace the engine.
18
Inspect the torque converter clutch control.
(See ROAD TEST [SJ6A-EL].)
Does the torque converter clutch control operate properly?
Yes
Inspect for the following:
•  Blockage at intake-air system (between MAF sensor and intake ports)
•  MAF sensor installation
No
Repair or replace the malfunctioning parts, according to the torque converter clutch control inspection results.
19
•  Verify test results.
―  If normal, return to the diagnostic index to service any additional symptoms.
―  If the malfunction remains, inspect the related Service Bulletins and/or the On-line Repair Information and perform the repair or diagnosis.