NO.9 FAST IDLE/RUNS ON [SKYACTIV-G 2.5T]

id0103q4801500

9

FAST IDLE/RUNS ON
DESCRIPTION
•  Engine speed continues at fast idle after warm-up.
•  Engine runs after ignition is switched off.
POSSIBLE CAUSE
•  Cooling system malfunction
•  PCM DTC is stored
•  Accelerator pedal stuck depressed
•  Erratic signal to PCM
?  APP sensor or related circuit malfunction
?  Communication error between TCM and PCM
?  ECT sensor or related circuit malfunction
?  A/F sensor or related circuit malfunction
?  HO2S or related circuit malfunction
?  Improper air/fuel mixture ratio control operation
•  Improper load signal input
?  Improper A/C request signal
•  Improper operation of drive-by-wire control system
•  Throttle body malfunction
•  Fuel injector malfunction
•  Spill valve control solenoid valve (built-into high pressure fuel pump) malfunction
•  Improper operation of cruise control system
•  Air leakage from intake-air 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 [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
INSPECT COOLING SYSTEM FOR MALFUNCTION
•  Access the ECT PID using the M-MDS.
•  Start the engine and warm it up completely.
•  Is the ECT PID value between 82—112 °C {180—234 °F}?
Yes
Go to the next step.
No
ECT PID value is higher than 112 °C {234 °F}:
•  Perform the symptom troubleshooting "NO.17 COOLING SYSTEM CONCERNS-OVERHEATING".
ECT PID value is less than 82 °C {180 °F}:
•  Perform the symptom troubleshooting "NO.18 COOLING SYSTEM CONCERNS-RUNS COLD".
2
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.
3
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
?  ECT
?  O2S11
?  O2S12
?  SHRTFT1
?  LONGFT1
•  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.
ECT PID is not as specified:
•  Inspect the ECT sensor.
O2S11, SHRTFT1, LONGFT1 PIDs are not as specified:
•  Inspect the A/F sensor.
O2S12 PID is not as specified:
•  Inspect the HO2S.
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.
4
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”.
5
DETERMINE IF MALFUNCTION CAUSE IS DRIVE-BY-WIRE CONTROL SYSTEM OR OTHER
•  Will the engine run smoothly at part throttle?
Yes
Go to Step 7.
No
Go to the next step.
6
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.
7
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.
8
INSPECT HIGH PRESSURE FUEL PUMP
•  Inspect the high pressure fuel pump.
•  Is there any malfunction?
Yes
Replace the high pressure fuel pump.
(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
No
Go to the next step.
9
INSPECT CRUISE CONTROL SYSTEM
•  Inspect the operation of cruise control system.
•  Does the cruise control system work properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
10
INSPECT INTAKE-AIR SYSTEM FOR AIR LEAKAGE
•  Inspect for leakage in intake-air system.
•  Is there any leakage?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Injector driver malfunction.
•  Replace the PCM.
If the problem remains, overhaul the engine.
11
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.