NO. 10 Low Idle/Stalls During Deceleration: Notes

NO. 10 LOW IDLE/STALLS DURING DECELERATION (SKYACTIV-G 2.5T) DESCRIPTION AND POSSIBLE CAUSE

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 No. 1 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 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 .) 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 .) (See After Service Precaution .) 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.

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 No. 1 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

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 .)
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 .) (See After Service Precaution .)

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.