NO.9 FAST IDLE/RUNS ON [SKYACTIV-G 2.5 (WITH CYLINDER DEACTIVATION)]

id0103q5801500

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 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
•  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.
•  Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE SERVICE PRECAUTION” and “AFTER SERVICE PRECAUTION” described in this manual. (See BEFORE SERVICE PRECAUTION [SKYACTIV-G 2.5 (WITH CYLINDER DEACTIVATION)].) (See AFTER SERVICE PRECAUTION [SKYACTIV-G 2.5 (WITH CYLINDER DEACTIVATION)].)
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 matter.

Caution
•  Verify the malfunction symptom according to not only the PID value but also the symptom troubleshooting.

Related PIDs

Item (definition)

Unit/Condition

Definition

Condition/Specification (Reference)
AC_REQ
Off/On
A/C request signal
•  A/C switch off: Off
•  A/C switch on: On
APP1
%
APP sensor No.1
•  Accelerator pedal released: Approx. 15%
•  Accelerator pedal depressed: Approx. 90.58%
V
•  Accelerator pedal released: Approx. 0.75 V
•  Accelerator pedal depressed: Approx. 4.52 V
APP2
%
APP sensor No.2
•  Accelerator pedal released: Approx. 7.45%
•  Accelerator pedal depressed: Approx. 45.49%
V
•  Accelerator pedal released: Approx. 0.38 V
•  Accelerator pedal depressed: Approx. 2.26 V
ECT
°C, °F
Engine coolant temperature
•  Displays ECT
V
•  ECT is 20 °C {68 °F}: Approx. 3.10 V
•  ECT is 40 °C {104 °F}: Approx. 2.16 V
•  ECT is 60 °C {140 °F}: Approx. 1.40 V
•  ECT is 80 °C {176 °F}: Approx. 0.87 V
•  ECT is 100 °C {212 °F}: Approx. 0.54 V
FUEL_PRES
KPa {MPa}, mBar {Bar}, psi, in H20
Fuel pressure
•  Displays fuel pressure
V
Idle (ECT 80 °C {176 °F})
•  Fuel pressure is 10 MPa {102 kgf/cm2, 1450 psi}: Approx. 1.4 V
LOAD
%
Engine load
•  Idle (after warm up): Approx. 16.07%
•  Racing (engine speed is 2,000 rpm): Approx. 13.33%
•  Racing (engine speed is 4,000 rpm): Approx. 15.29%
LONGFT1
%
Long term fuel trim
•  Idle (after warm up): Approx. -3.9%
•  Racing (engine speed is 2,000 rpm): Approx. -0.78%
•  Racing (engine speed is 4,000 rpm): Approx. -0.78%
O2S11
µA
A/F sensor
•  Idle (after warm up): Approx. -39 µA
•  Deceleration fuel cut (accelerator pedal released from engine speed of 4,000 rpm or more): Approx. 3.84 mA
O2S12
V
HO2S
•  Idle (after warm up): 0—1.0 V
•  Deceleration fuel cut (accelerator pedal released from engine speed of 4,000 rpm or more): Approx. 0 V
RPM
RPM
Engine speed
•  Displays engine speed
SHRTFT1
%
Short term fuel trim
•  Idle (after warm up): Approx. 2.34%
•  Racing (engine speed is 2,000 rpm): Approx. 3.9%
•  Racing (engine speed is 4,000 rpm): Approx. 1.56%
TP_REL
%
Throttle position signal (relative value)
•  Accelerator pedal released: Approx. 12%
•  Accelerator pedal depressed: Approx. 82%
VSS
KPH, MPH
Vehicle speed
•  Displays vehicle speed

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 any DTCs using the M-MDS.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [PCM (SKYACTIV-G 2.5 (WITH CYLINDER DEACTIVATION))].)
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 malfunction 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 using the 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 2.5 (WITH CYLINDER DEACTIVATION)].)
No
Go to the next step.
9
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.
10
Verify the 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 On-line Repair Information and perform 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.