DESCRIPTION

Fuel trim system too lean

DETECTION CONDITION

Determination conditions

• Any one of the following conditions is met:

• The sum of the fuel feedback correction amount (SHRTFT1) and the fuel learning correction amount (LONGFT1) is the specified value (30 %) or more, and 10 s or more have elapsed with the fuel learning correction amount (LONGFT1) at the specified value (15 %) or more.

• While the engine is idling or the vehicle is driven, the fuel feedback correction amount reaches the upper limit (25 % or more) for 20 s or more.

Preconditions

• Engine coolant temperature: 0—45 °C {32—113 °F}, 60 °C {140 °F} or more^*1

• ^*1: Value can be verified by displaying PIDs using M-MDS

Malfunction determination period

• 10 s or 20 s period

Drive cycle

• 2

Self test type

• CMDTC self test

Sensor used

• A/F sensor

FAIL-SAFE FUNCTION

• Not applicable

VEHICLE STATUS WHEN DTCs ARE OUTPUT

• Illuminates check engine light.

POSSIBLE CAUSE

• Erratic signal to PCM

• ECT sensor No.1 signal malfunction

• MAF sensor signal malfunction

• MAP sensor signal malfunction

• IAT sensor No.2 signal malfunction

• Related connector or terminals malfunction

• Related wiring harness malfunction

• High-pressure side fuel delivery system malfunction

• Fuel pressure sensor malfunction

• Relief valve (built-into 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

• High pressure fuel pump malfunction

• Fuel leakage in fuel line

• Low-pressure side fuel delivery system malfunction

• Fuel filter clogged (built-into fuel pump unit)

• Low pressure side fuel line restriction (between fuel pump unit and high pressure fuel pump)

• Fuel pump unit malfunction

• Pressure regulator (built-into fuel pump unit) malfunction

• Fuel injector malfunction

• Improper operation of fuel injector

• Fuel injector related wiring harness malfunction

• Improper operation of purge control system

• Purge solenoid valve malfunction

• Purge solenoid hoses improper connection

• PCV valve malfunction

• MAF sensor malfunction

• Air cleaner element malfunction

• MAP sensor malfunction

• Air suction in intake air system

• 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

• A/F sensor malfunction

• A/F sensor loose

• Exhaust system leakage

• Poor fuel quality

• PCM malfunction

Item

Definition

Unit

Condition/Specification

APP

Accelerator pedal opening angle (relative value) with the fully released status as 0% and fully depressed status as 100%

%

• Accelerator pedal released: Approx. 0%

• Accelerator pedal fully depressed: Approx. 100%

ECT

Engine coolant temperature input from ECT sensor No.1

°C, °F

• Displays ECT

ECT sensor No.1 voltage

V

Ignition switched ON (engine off)

• ECT is 92 °C {198 °F}: Approx. 0.65 V

Idle (after warm up)

• ECT is 93 °C {199 °F}: Approx. 0.64 V

Racing (Engine speed is 2,000 rpm)

• ECT is 92 °C {198 °F}: Approx. 0.66 V

Racing (Engine speed is 4,000 rpm)

• ECT is 93 °C {199 °F}: Approx. 0.64 V

EVAPCP

Purge solenoid valve control duty value

%

• Idle (after warm up): 0% (ECT is 59 °C {140 °F} or less)

• Racing (Engine speed 2,000 rpm): 0% (ECT is 94 °C {201 °F})

• Racing (Engine speed 4,000 rpm): Approx. 10.1% (ECT is 94 °C {201 °F})

FP

Fuel pump relay operation status

Off/On

• Ignition switched ON (engine off): Off

• Cranking: On

• Idle (after warm up): On

FUEL_PRES

Fuel pressure input from fuel pressure sensor

KPa , mBar , psi, in H20

• Displays fuel pressure

Fuel pressure sensor voltage

V

Ignition switched ON (engine off)

• Fuel pressure is approx. 3.6 MPa {37 kgf/cm², 522 psi}: Approx. 1.01 V (ECT is 92 °C {198 °F})

Idle (after warm up)

• Fuel pressure is approx. 3.45 MPa {35.2 kgf/cm², 500 psi}: Approx. 1 V (ECT is 92 °C {198 °F})

Racing (Engine speed is 2,000 rpm)

• Fuel pressure is approx. 3.21 MPa {32.7 kgf/cm², 466 psi}: Approx. 0.96 V (ECT is 86 °C {187 °F})

Racing (Engine speed is 4,000 rpm)

• Fuel pressure is approx. 5.59 MPa {57.0 kgf/cm², 811 psi}: Approx. 1.29 V (ECT is 84 °C {183 °F})

MAF

Mass air flow input from MAF sensor

g/Sec

• Displays MAF

MAF sensor voltage

V

• Ignition switched ON (engine off) (MAF: 0.39 g/s {0.052 lb/min}): Approx. 0.72 V (ECT is 89 °C {192 °F})

• Idle (after warm up) (MAF: 4.29 g/s {0.567 lb/min}): Approx. 1.15 V (ECT is 88 °C {190 °F})

• Racing (engine speed is 2,000 rpm) (MAF: 4.32 g/s {0.571 lb/min}): Approx. 1.15 V (ECT is 89 °C {192 °F})

• Racing (engine speed is 4,000 rpm) (MAF: 12.71 g/s {1.681 lb/min}): Approx. 1.66 V (ECT is 89 °C {192 °F})

MAP

Manifold absolute pressure input from MAP sensor

KPa , mBar , psi, in H20

• Displays MAP

MAP_V

MAP sensor voltage

V

• Ignition switched ON (engine off) (MAP:101 kPa {1.03 kgf/cm², 14.6 psi}): Approx. 4.08 V (ECT is 89 °C {192 °F})

• Idle (after warm up) (MAP: 31 kPa {0.32 kgf/cm², 4.5 psi}): Approx. 1.25 V (ECT is 88 °C {190 °F})

• Racing (engine speed is 2,000 rpm) (MAP: 32 kPa {0.33 kgf/cm², 4.6 psi}): Approx. 1.31 V (ECT is 89 °C {192 °F})

• Racing (engine speed is 4,000 rpm) (MAP: 49 kPa {0.50 kgf/cm², 7.1 psi}): Approx. 2.03 V (ECT is 89 °C {192 °F})

IAT2

Intake air temperature (No.2) input from IAT sensor No.2

°C, °F

• Displays IAT (No.2)

IAT sensor No.2 voltage

V

• IAT2 is 65 °C {149 °F}: Approx. 1.7 V

• IAT2 is 66 °C {151 °F}: Approx. 1.65 V

O2S11

A/F sensor current

µA

• Idle (after warm up): −59 µA (ECT is 92 °C {198 °F})

• Deceleration fuel cut (accelerator pedal released from engine speed of 4,000 rpm or more): Approx. 3.48 mA (ECT is 92 °C {198 °F})

TP_REL

Throttle valve opening angle (relative value) with value at throttle valve fully close timing as the start point

%

• Accelerator pedal released: Approx. 12.15%

• Accelerator pedal fully depressed: Approx. 81.96%

VT_EX_ACT

Actual exhaust variable valve timing control

• Retard amount from max advance position

°(deg)

• Displays actual exhaust variable valve timing—retard amount from max advance position

Ignition switched ON (engine off)

• Approx. 0 ° (ECT is 89 °C {192 °F})

Idle (after warm up)

• Approx. 0.25 ° (ECT is 91 °C {196 °F})

Racing (engine speed is 2,000 rpm)

• Approx. 21.43 ° (ECT is 89 °C {192 °F})

Racing (engine speed is 4,000 rpm)

• Approx. 35.93 ° (ECT is 88 °C {190 °F})

VT_EX_DES

Target exhaust variable valve timing control

• Retard amount from max advance position

°(deg)

• Displays target exhaust variable valve timing—retard amount from max advance position

Ignition switched ON (engine off)

• Approx. 0 ° (ECT is 89 °C {192 °F})

Idle (after warm up)

• Approx. 0 ° (ECT is 91 °C {196 °F})

Racing (engine speed is 2,000 rpm)

• Approx. 22.87 ° (ECT is 89 °C {192 °F})

Racing (engine speed is 4,000 rpm)

• Approx. 36 ° (ECT is 88 °C {190 °F})

VT_IN_ACT

Actual intake variable valve timing control

• Advance amount from max retard position

°(deg)

• Displays actual intake variable valve timing—advance amount from max retard position

Ignition switched ON (engine off)

• Approx. 28 ° (ECT is 89 °C {192 °F})

Idle (after warm up)

• Approx. 24.75 ° (ECT is 91 °C {196 °F})

Racing (engine speed is 2,000 rpm)

• Approx. 18.62 ° (ECT is 89 °C {192 °F})

Racing (engine speed is 4,000 rpm)

• Approx. 0.18 ° (ECT is 88 °C {190 °F})

VT_IN_DES

Target intake variable valve timing control

• Advance amount from max retard position

°(deg)

• Displays target intake variable valve timing—advance amount from max retard position

Ignition switched ON (engine off)

• Approx. 27.81 ° (ECT is 89 °C {192 °F})

Idle (after warm up)

• Approx. 24.56 ° (ECT is 91 °C {196 °F})

Racing (engine speed is 2,000 rpm)

• Approx. 18.62 ° (ECT is 89 °C {192 °F})

Racing (engine speed is 4,000 rpm)

• Approx. 0 ° (ECT is 88 °C {190 °F})

Item

Definition

Unit

Operation

INJ_1

Fuel injector No.1

OFF

• Select OFF to forcibly stop fuel injector No.1.

INJ_2

Fuel injector No.2

OFF

• Select OFF to forcibly stop fuel injector No.2.

INJ_3

Fuel injector No.3

OFF

• Select OFF to forcibly stop fuel injector No.3.

INJ_4

Fuel injector No.4

OFF

• Select OFF to forcibly stop fuel injector No.4.

STEP

INSPECTION

RESULTS

ACTION

1

• Verify related Service Bulletins and/or on-line repair information availability.

• Is any related repair information available?

Yes

Perform repair or diagnosis according to the available repair information.

• If the vehicle is not repaired, go to the next step.

No

Go to the next step.

2

• Is the DTC P0171:00 on FREEZE FRAME DATA?

Yes

Go to the next step.

No

Go to the troubleshooting procedure for DTC on FREEZE FRAME DATA.

(See DTC TABLE [PCM (SKYACTIV-G 2.0)].)

3

NOTE:

• Recording can be facilitated using the screen capture function of the PC.

• Record the FREEZE FRAME DATA/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (fuel system related) on the repair order.

—

Go to the next step.

4

• Start the engine.

• Access the following PIDs using the M-MDS:

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• ECT

• APP

• TP_REL

• Is there any signal that is far out of specification?

  (See PCM INSPECTION [SKYACTIV-G 2.0].)

Yes

Inspect the suspected sensor and related wiring harness.

• If there is any malfunction:

• Repair or replace the malfunctioning part.

• Go to the troubleshooting procedure to perform the procedure from Step 19.

• If there is no malfunction:

• Go to the next step.

No

Go to the next step.

5

• Start the engine.

• Access the following PIDs using the M-MDS:

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• FUEL_PRES

• FP

• EVAPCP

• MAF

• MAP

• MAP_V

• IAT2

• VT_EX_ACT

• VT_IN_ACT

• When the following parts are shaken, does the PID value include a PID item which has changed?

• Fuel pressure sensor

• Purge solenoid valve

• MAF sensor

• MAP sensor/IAT sensor No.2

• OCV

• Electric variable valve timing motor/driver

• PCM

Yes

Repair or replace the applicable connector parts.

Go to the troubleshooting procedure to perform the procedure from Step 19.

No

Go to the next step.

6

• Switch the ignition off.

• Reconnect all disconnected connectors.

• Start the engine and idle it.

• Access the FUEL_PRES PID using the M-MDS.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Is the FUEL_PRES PID value approx. 3 MPa {31 kgf/cm², 435 psi}?

Yes

Go to the next step.

No

FUEL_PRES PID value is lower than 3 MPa {31 kgf/cm², 435 psi}:

• Go to the troubleshooting procedure to perform the procedure from Step 1.

FUEL_PRES PID value is higher than 3 MPa {31 kgf/cm², 435 psi}:

• Go to Step 8.

7

NOTE:

• Verify the fuel pressure on the low pressure side with the operation of the high pressure fuel pump turned off.

• Bleed the remaining pressure in the fuel line using the following procedure.

• Switch the ignition off.

• Disconnect the high pressure fuel pump connector.

• Disconnect the fuel pump relay.

• Start the engine and wait until the engine stalls.

• Switch the ignition off.

• Install the fuel pump relay.

• Switch the ignition ON (engine off).

• Display PID FUEL_PRES and simulation item FP using the M-MDS.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Turn simulation item FP on.

• Is the FUEL_PRES PID value 430 kPa {4.38 kgf/cm², 62.4 psi} or more?

Yes

Go to the next step.

No

Go to the troubleshooting procedure to perform the procedure from Step 5.

8

• Switch the ignition off.

• Reconnect all disconnected connectors.

• Start the engine and idle it.

• Access the following simulation items using the M-MDS:

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• INJ_1

• INJ_2

• INJ_3

• INJ_4

• Turn each fuel injector from on to off using the simulation items.

• Does the vibration during idling worsen?

Yes

Go to the next step.

No

Go to the troubleshooting procedure to perform the procedure from Step 6.

9

• Start the engine and idle it.

• Access the EVAPCP PID using the M-MDS.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Is the EVAPCP PID value normal?

Yes

Go to the next step.

No

Go to the troubleshooting procedure to perform the procedure from Step 7.

10

• Start the engine and idle it.

• Access the MAF PID using the M-MDS.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Is the MAF PID value normal?

Yes

Go to the next step.

No

Go to the troubleshooting procedure to perform the procedure from Step 9.

11

• Start the engine and idle it.

• Access the following PIDs using the M-MDS:

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• MAP

• MAP_V

• Are all items normal?

Yes

Go to the next step.

No

Go to the troubleshooting procedure to perform the procedure from Step 11.

12

• Start the engine and idle it.

• Access the following PIDs using the M-MDS:

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• VT_IN_ACT

• VT_IN_DES

• Depress the accelerator pedal to increase the engine speed.

• Does the monitor value of the PID item VT_IN_ACT conform to the VT_IN_DES PID value?

Yes

Go to the next step.

No

Go to the troubleshooting procedure to perform the procedure from Step 13.

13

• Start the engine and idle it.

• Access the following PIDs using the M-MDS:

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• VT_EX_ACT

• VT_EX_DES

• Depress the accelerator pedal to increase the engine speed.

• Does the monitor value of the PID item VT_EX_ACT conform to the VT_EX_DES PID value?

Yes

Go to the next step.

No

Go to the troubleshooting procedure to perform the procedure from Step 16.

14

• Access the O2S11 PID using the M-MDS.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Is the O2S11 PID value normal?

Yes

Go to the next step.

No

Go to the troubleshooting procedure to perform the procedure from Step 17.

15

• Switch the ignition off, then ON (engine off).

• Retrieve the PCM DTCs using the M-MDS.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [PCM (SKYACTIV-G 2.0)].)

Go to the troubleshooting procedure to perform the procedure from Step 1.

No

Go to the troubleshooting procedure to perform the procedure from Step 1.

STEP

INSPECTION

RESULTS

ACTION

1

• Verify the remaining amount of fuel.

• Is there a lack of fuel?

Yes

Refill the fuel, then go to Step 19.

No

Go to the next step.

2

• Inspect the fuel pressure sensor.

  (See FUEL PRESSURE SENSOR INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the fuel distributor, then go to Step 19.

(See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

3

• Inspect the high pressure fuel pump.

  (See HIGH PRESSURE FUEL PUMP INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the high pressure fuel pump, then go to Step 19.

(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

4

• Inspect the fuel system pipes (low to high pressure sides) for fuel leakage and restriction.

• Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results, then go to Step 19.

No

Go to the next step.

5

• Inspect the fuel pump unit.

  (See FUEL PUMP UNIT INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the fuel pump unit, then go to Step 19.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

6

• Inspect the fuel injector.

  (See FUEL INJECTOR INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the fuel injector, then go to Step 19.

(See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

7

• Inspect the purge solenoid valve.

  (See PURGE SOLENOID VALVE INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the purge solenoid valve, then go to Step 19.

(See PURGE SOLENOID VALVE REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

8

• Inspect the PCV valve.

  (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [SKYACTIV-G 2.0].)

Yes

Replace the PCV valve, then go to Step 19.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

9

• Inspect the MAF sensor.

  (See MASS AIR FLOW (MAF) SENSOR INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the MAF sensor/IAT sensor No.1, then go to Step 19.

(See MASS AIR FLOW (MAF) SENSOR/INTAKE AIR TEMPERATURE (IAT) SENSOR NO.1 REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

10

• Inspect the air cleaner element.

  (See AIR CLEANER ELEMENT INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the air cleaner element, then go to Step 19.

(See AIR CLEANER ELEMENT REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

11

• Reconnect all disconnected connectors.

• Inspect the MAP sensor.

  (See MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the MAP sensor/IAT sensor No.2, then go to Step 19.

(See MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR/INTAKE AIR TEMPERATURE (IAT) SENSOR NO.2 REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

12

• Visually inspect for loose, cracked or damaged hoses on intake air system.

• Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results, then go to Step 19.

No

Go to the next step.

13

• Inspect the electric variable valve timing driver.

  (See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the electric variable valve timing motor/driver, then go to Step 19.

(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

14

• Inspect the electric variable valve timing motor.

  (See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the electric variable valve timing motor/driver, then go to Step 19.

(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

15

• Inspect the electric variable valve timing actuator.

  (See ELECTRIC VARIABLE VALVE TIMING ACTUATOR INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the electric variable valve timing actuator, then go to Step 19.

(See ELECTRIC VARIABLE VALVE TIMING ACTUATOR, HYDRAULIC VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

16

• Inspect the OCV.

  (See OIL CONTROL VALVE (OCV) INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the OCV, then go to Step 19.

(See OIL CONTROL VALVE (OCV) REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

17

• Inspect the A/F sensor.

  (See AIR FUEL RATIO (A/F) SENSOR INSPECTION [SKYACTIV-G 2.0].)

• Is there any malfunction?

Yes

Replace the A/F sensor, then go to Step 19.

(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

Go to the next step.

18

• Verify the exhaust gas leakage from the exhaust system. (between A/F sensor and HO2S)

• Is there any malfunction?

Yes

Repair or replace the malfunctioning part according to the inspection results, then go to the next step.

No

Go to the next step.

19

• Always reconnect all disconnected connectors.

• Clear the DTC from the PCM memory using the M-MDS.

  (See CLEARING DTC [PCM (SKYACTIV-G 2.0)].)

• Implement the repeatability verification procedure.

  (See Repeatability Verification Procedure.)

• Perform the Pending Trouble Code Access Procedure.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Is the PENDING CODE for this DTC present?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the PCM.

  (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

No

DTC troubleshooting completed.