NO.10 LOW IDLE/STALLS DURING DECELERATION [SKYACTIV-G 2.5T]

id0103q4801600

10

LOW IDLE/STALLS DURING DECELERATION
DESCRIPTION
•  Engine stops unexpectedly at beginning of deceleration or recovery from deceleration.
POSSIBLE CAUSE
•  PCM DTC is stored
•  Erratic signal to PCM
?  APP sensor or related circuit malfunction
?  Brake switch or related circuit malfunction
?  Communication error between TCM and PCM
?  ECT sensor or related circuit malfunction
?  MAF sensor or related circuit malfunction
?  MAP sensor or related circuit malfunction
?  A/F sensor or related circuit malfunction
?  HO2S or related circuit malfunction
?  TP sensor or related circuit malfunction
?  Generator malfunction (part, system, control malfunction)
•  Amount of generator voltage is large
?  Improper air/fuel mixture ratio control
•  Improper operation of A/C magnetic clutch
•  Improper operation of drive-by-wire control system
•  Incorrect fuel injection timing
•  Fuel injector malfunction
•  Purge solenoid valve malfunction
•  Poor fuel quality
•  Air leakage from intake-air system
•  Vacuum leakage
•  Intake-air system restriction
•  Fuel leakage
•  Engine mount installation loose
•  Erratic signal from CKP sensor
?  Loose installation
?  Damaged trigger wheel (crankshaft pulley)
?  Open or short circuit in related wiring harness
•  Erratic signal from intake CMP sensor
?  Loose installation
?  Damaged trigger wheel (intake camshaft)
?  Damaged trigger wheel (exhaust camshaft)
?  Open or short circuit in related wiring harness
•  Inadequate fuel pressure (high or low pressure side)
?  Fuel pressure sensor or related circuit malfunction
?  High pressure fuel pump malfunction
?  Spill valve control solenoid valve control circuit malfunction (damage to driver in PCM caused by short circuit to ground system)
?  Spill valve control solenoid valve (built-into high pressure fuel pump) malfunction
?  Relief valve (built-into high pressure fuel pump) malfunction
?  Fuel line restriction
?  Fuel filter clogged (built-into fuel pump unit)
?  Fuel pump unit malfunction
•  ATX malfunction
•  Low engine compression
•  Improper intake valve timing
•  Improper exhaust valve timing
•  Improper operation of electric variable valve timing control system
?  Electric variable valve timing driver malfunction
?  Electric variable valve timing motor malfunction
?  Electric variable valve timing actuator malfunction
•  Improper operation of hydraulic variable valve timing control system
•  Injector driver (built-into PCM) malfunction
POSSIBLE CAUSE
Warning
•  The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services:
?  Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.
?  Highly pressurized fuel may spray out if the fuel line is cut. Due to the following dangers occurring with a fuel spray, always complete the “Fuel Line Safety Procedure” to prevent the fuel from spraying. (See BEFORE SERVICE PRECAUTION [SKYACTIV-G 2.5T].)
•  Fuel may cause irritation if it comes in contact with skin and eyes.
•  If fuel ignites and causes a fire, it may lead to serious injury or death, and damage to property and facilities.
?  Fuel is highly flammable and dangerous. Fuel line spills and leakage can cause serious injury or death, and damage to equipment. Always refer to the “Quick Release Connector Removal/Installation (fuel system)” before performing the fuel hose installation, and execute the “Fuel Leakage Inspection” after installation. (See QUICK RELEASE CONNECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].) (See AFTER SERVICE PRECAUTION [SKYACTIV-G 2.5T].)
Caution
•  Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and quick release connector. Always clean the 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
VERIFY IF MALFUNCTION INCLUDES HARD ENGINE STARTING
•  Is the engine unable to start after it has stalled?
Note
•  If the ignition is not switched off (to LOCK or ACC) after the engine stalls, and then an engine restart is attempted, the PCM corrects the difference between CKP sensor and CMP sensor signals caused by engine stalling, which may result in more time needed to restart the engine.
Yes
If the engine is unable to start, perform the symptom troubleshooting “NO.3 WILL NOT CRANK” and “NO.6 CRANKS NORMALLY BUT WILL NOT START”.
(See NO.3 WILL NOT CRANK [SKYACTIV-G 2.5T].)
(See NO.6 CRANKS NORMALLY BUT WILL NOT START [SKYACTIV-G 2.5T].)
No
Go to the next step.
2
VERIFY IF MALFUNCTION INCLUDES ROUGH IDLING
•  Does the engine idle rough?
Yes
Perform the symptom troubleshooting “NO.8 ENGINE RUNS ROUGH/ROLLING IDLE”.
(See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [SKYACTIV-G 2.5T].)
No
Go to the next step.
3
VERIFY PCM DTC
•  Retrieve PCM DTCs using the M-MDS.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [PCM (SKYACTIV-G 2.5T)].)
No
Go to the next step.
4
VERIFY CURRENT INPUT SIGNAL STATUS
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
?  ECT
?  MAF
?  MAP
?  MAP_V
?  TP_REL
?  O2S11
?  O2S12
?  SHRTFT1
?  LONGFT1
?  ALTT V (without i-ELOOP)
•  Do the PIDs indicate the correct values under the trouble condition?
Yes
Go to the next step.
No
APP1, APP2 PIDs are not as specified:
•  Inspect the APP sensor.
BOO PID is not as specified:
•  Inspect the brake switch.
ECT PID is not as specified:
•  Inspect the ECT sensor.
MAF PID is not as specified:
•  Inspect the MAF sensor.
MAP, MAP_V PIDs are not as specified:
•  Inspect the MAP sensor.
TP_REL PID is not as specified:
•  Inspect the TP sensor.
O2S11, SHRTFT1, LONGFT1 PIDs are not as specified:
•  Inspect the A/F sensor.
O2S12 PID is not as specified:
•  Inspect the HO2S.
ALTT V PID is not as specified: (without i-ELOOP)
•  Inspect the generator.
Repair or replace the malfunctioning part according to the inspection results.
•  If the malfunction remains:
?  Inspect communication error between TCM and PCM.
•  Repair or replace the malfunctioning part according to the inspection results if necessary.
?  Perform the “INTERMITTENT CONCERN TROUBLESHOOTING” procedure.
5
DETERMINE IF MALFUNCTION CAUSE IS A/C REQUEST SIGNAL OR OTHER
•  Access the AC_REQ PID using the M-MDS.
•  Monitor the AC_REQ PID while turning on and off the air conditioner with switch on the control panel.
•  Does the AC_REQ PID value change from on to off according to switch control panel?
Yes
Go to the next step.
No
If the AC_REQ PID is always ON:
•  Perform the symptom troubleshooting “NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”.
If the AC_REQ PID is always OFF:
•  Perform the symptom troubleshooting “NO.23 A/C DOES NOT WORK SUFFICIENTLY”.
6
DETERMINE IF MALFUNCTION CAUSE IS DRIVE-BY-WIRE CONTROL SYSTEM OR OTHER
•  Will the engine run smoothly at part throttle?
Yes
Go to Step 8.
No
Go to the next step.
7
INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION
•  Perform the Electronic Control Throttle Operation Inspection.
•  Does the drive-by-wire control system work properly?
Yes
Visually inspect the throttle body (damage/scratching).
•  If there is any malfunction:
?  Repair or replace the malfunctioning part according to the inspection results.
•  If there is no malfunction:
?  Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
8
INSPECT FUEL INJECTOR OPERATION
•  Perform the Fuel Injector Operation Inspection.
•  Do the fuel injectors operate properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
9
INSPECT PURGE CONTROL SYSTEM OPERATION
•  Perform the Purge Control System Inspection.
•  Does the purge solenoid valve work properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
10
INSPECT RELATED PART CONDITION
•  Inspect the following:
?  Fuel quality (proper octane, contamination, winter/summer blend)
?  Vacuum leakage
?  Intake-air system restriction
?  Fuel leakage in fuel system
?  CKP sensor and intake CMP sensor
•  Installation condition
•  Damaged trigger wheel (intake camshaft)
?  Exhaust CMP sensor
•  Installation condition
•  Damaged trigger wheel (exhaust camshaft)
•  Is there any malfunction?
Yes
Service if necessary.
•  Repeat this step.
No
Go to the next step.
11
INSPECT FUEL PRESSURE (HIGH-SIDE)
•  Start the engine and warm it up completely.
•  Access the FUEL_PRES PID using the M-MDS at idle.
•  Is the FUEL_PRES PID value approx. 3 MPa {31 kgf/cm2, 435 psi}?
Yes
Go to Step 15.
No
Lower than 3 MPa {31 kgf/cm2, 435 psi}:
•  Inspect the following:
?  Fuel leakage at the fuel line and fuel injector
?  Fuel pump
•  Perform the Fuel Pump (Low-pressure Side) Operation Inspection.
?  Fuel pressure sensor
?  High pressure fuel pump
•  If there is any malfunction:
?  Repair or replace the malfunctioning part according to the inspection results.
•  If there is no malfunction:
?  Go to Step 14.
Higher than 3 MPa {31 kgf/cm2, 435 psi}:
•  Go to the next step.
12
DETERMINE IF MALFUNCTION CAUSE IS FUEL PRESSURE SENSOR OR HIGH PRESSURE FUEL PUMP
•  Is the vehicle acceleration performance normal?
Yes
Go to the next step.
No
Go to Step 14.
13
INSPECT HIGH FUEL PRESSURE SENSOR
•  Inspect the fuel pressure sensor.
•  Is there any malfunction?
Yes
Replace the fuel distributor.
(See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
No
Go to Step 15.
14
INSPECT SPILL VALVE CONTROL SOLENOID VALVE CONTROL CIRCUIT FOR SHORT TO GROUND
•  Switch the ignition off.
•  Disconnect the high pressure fuel pump and PCM connectors.
•  Inspect for continuity between high pressure fuel pump terminal A (wiring harness-side) and body ground.
•  Is there continuity?
Yes
Refer to the wiring diagram and verify whether or not there is a common connector between high pressure fuel pump terminal A and PCM terminal 1EE.
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has a short to ground.
If the malfunction remains:
•  Replace the PCM. (damage to driver in PCM)
No
Replace the high pressure fuel pump.
(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
15
INSPECT FUEL PRESSURE (LOW-SIDE)
•  Connect the fuel pressure gauge between fuel pump and high pressure fuel pump.
•  Measure the low side fuel pressure.
•  Is the low side fuel pressure within specification?
Specification:
•  545—695 kPa {5.56—7.08 kgf/cm2, 79.1—100.0 psi}
Yes
Go to the next step.
No
Inspect the following:
•  Fuel line restriction
•  Fuel filter clogged
?  If there is any malfunction:
•  Repair or replace the malfunctioning part according to the inspection results.
?  If there is no malfunction:
•  Replace the fuel pump unit.
16
INSPECT IF MALFUNCTION CAUSE IS ENGINE COMPRESSION OR INJECTOR DRIVER (PCM INTEGRATED)
•  Measure the compression pressure for each cylinder.
•  Are compression pressures within specification?
Yes
Go to Step 22.
No
Go to the next step.
17
INSPECT ELECTRIC VARIABLE VALVE TIMING DRIVER
•  Inspect the electric variable valve timing driver.
•  Is there any malfunction?
Yes
Replace the electric variable valve timing motor/driver.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
No
Go to the next step.
18
INSPECT ELECTRIC VARIABLE VALVE TIMING MOTOR
•  Inspect the electric variable valve timing motor.
•  Is there any malfunction?
Yes
Replace the electric variable valve timing motor/driver.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
No
Go to the next step.
19
INSPECT ELECTRIC VARIABLE VALVE TIMING ACTUATOR
•  Inspect the electric variable valve timing actuator.
•  Is there any malfunction?
Yes
Replace the electric variable valve timing actuator.
(See ELECTRIC VARIABLE VALVE TIMING ACTUATOR, HYDRAULIC VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
No
Go to the next step.
20
INSPECT HYDRAULIC VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION
•  Perform the Hydraulic Variable Valve Timing Control System Operation Inspection.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
21
INSPECT FOR MALFUNCTION DUE TO DEVIATED VALVE TIMING
•  Inspect the valve timing (timing chain installation condition).
•  Is the valve timing normal?
Yes
Inspect for the following engine internal parts:
•  Cylinder
•  Piston ring
•  Intake valve
•  Exhaust valve
•  Such as cylinder head gasket
?  If there is any malfunction:
•  Repair or replace the malfunctioning part according to the inspection results.
No
Adjust the valve timing to the correct timing.
22
INSPECT FOR MALFUNCTION DUE TO ENGINE MOUNT INSTALLATION LOOSE
•  Verify the engine mount installation condition.
•  Is the engine mount installation condition normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
23
VERIFY ATX DTC
•  Retrieve TCM DTCs using the M-MDS.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (GW6A-EL, GW6AX-EL)].)
No
Injector driver malfunction.
•  Replace the PCM.
If the problem remains, overhaul the engine.
24
Verify the test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If a 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, replace the PCM.