DTC P0171:00 [SKYACTIV-G 2.0]

id0102h1934200

DTC P0171:00

Fuel trim system too lean
DETECTION CONDITION
•  When any of the following conditions is met:
―  During idling or driving, the correction amount of the fuel feedback correction plus the fuel learning correction is a volume increase correction exceeding the specified value.
―  During idling or driving, the amount of the fuel feedback increase correction reaches the upper limit.
Diagnostic support note
•  This is a continuous monitor (fuel system).
•  The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
•  PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle.
•  FREEZE FRAME DATA (Mode 2)/Snapshot data is available.
•  The DTC is stored in the PCM memory.
FAIL-SAFE FUNCTION
—
POSSIBLE CAUSE
•  Erratic signal to PCM
―  APP sensor signal malfunction
―  ECT sensor signal malfunction
―  MAF sensor signal malfunction
―  IAT2 sensor signal malfunction
―  TP sensor signal malfunction
―  Related connector or terminals malfunction
―  Related wiring harness malfunction
•  Air suction in intake air system
•  MAF sensor malfunction
•  A/F sensor heater malfunction
•  A/F sensor malfunction
―  A/F sensor loose
―  Exhaust system leakage
―  A/F sensor deterioration
•  Improper operation of purge control system
―  Purge solenoid valve malfunction
―  Purge solenoid hoses improper connection
•  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
•  Improper operation of fuel injector
•  High-pressure side fuel delivery system malfunction
―  Fuel pressure sensor 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
―  High pressure fuel pump malfunction
•  Low-pressure side fuel delivery system malfunction
―  Low pressure side fuel line restriction (between fuel pump unit and high pressure fuel pump)
―  Fuel filter clogged
―  Pressure regulator (built-into fuel pump unit) malfunction
―  Fuel pump unit malfunction
•  Ignition system malfunction
―  Spark plug malfunction
―  Ignition coil malfunction
―  Ignition coil related wiring harness malfunction
•  Insufficient engine compression
•  Misfire
•  PCM malfunction
SYSTEM WIRING DIAGRAM
—

Diagnostic Procedure

STEP

INSPECTION

ACTION
1
IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA (MODE 2)
•  Perform the Freeze Frame PID Data Access Procedure.
•  Is the DTC P0171:00 on FREEZE FRAME DATA (Mode 2)?
Yes
Go to the next step.
No
Go to the troubleshooting procedure for DTC on FREEZE FRAME DATA (Mode 2).
(See DTC TABLE [SKYACTIV-G 2.0].)
2
VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED
•  Have the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (fuel system related) been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
3
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
4
VERIFY RELATED PENDING CODE AND/OR DTC
•  Switch the ignition to off, then to ON (engine off).
•  Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure.
•  Are any other PENDING CODEs and/or DTCs present?
Yes
If misfire DTC is present:
•  Go to Step 7.
If other DTC is present:
•  Go to the applicable DTC inspection.
No
If drive ability concern is present:
•  Go to Step 7.
If drive ability concern is not present:
•  Go to the next step.
5
VERIFY CURRENT INPUT SIGNAL STATUS
•  Access the following PIDs using the M-MDS:
―  APP1
―  APP2
―  ECT
―  MAF
―  IAT2
―  TP REL
•  Is there any signal that is far out of specification when the ignition is switched to ON and the engine runs?
Yes
Inspect the suspected sensor and related wiring harness.
Repair or replace the malfunctioning part according to the inspection results, then go to Step 26.
No
Go to the next step.
6
VERIFY CURRENT INPUT SIGNAL STATUS UNDER FREEZE FRAME DATA (MODE 2) CONDITION
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 same PIDs as in Step 5 while simulating under the FREEZE FRAME DATA (Mode 2) conditions.
•  Is there any signal which causes drastic changes?
Yes
Inspect the suspected sensor and related wiring harness.
Repair or replace the malfunctioning part according to the inspection results, then go to Step 26.
No
Go to the next step.
7
VERIFY CURRENT INPUT SIGNAL STATUS OF MAF SENSOR
•  Start the engine.
•  Access the MAF PID using the M-MDS.
•  Verify that the MAF PID value changes quickly while increasing (racing) the engine rpm.
•  Is the MAF PID value normal?
Yes
Go to Step 9.
No
Go to the next step.
8
INSPECT INTAKE AIR SYSTEM FOR EXCESSIVE AIR SUCTION
•  Visually inspect for loose, cracked or damaged hoses on intake air system.
Note
•  Engine speed may change when rust penetrating agent is sprayed on the air suction area.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 26.
No
Replace the MAF sensor/IAT sensor No.1, then go to Step 26.
(See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
9
INSPECT A/F SENSOR HEATER
•  Inspect the A/F sensor heater.
•  Is there any malfunction?
Yes
Replace the A/F sensor, then go to Step 26.
(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
No
Go to the next step.
10
VERIFY CURRENT INPUT SIGNAL STATUS OF A/F SENSOR
•  Reconnect all disconnected connectors.
•  Inspect the A/F sensor.
•  Is there any malfunction?
Yes
Go to the next step.
No
Go to Step 13.
11
INSPECT INSTALLATION OF A/F SENSOR
•  Inspect installation of A/F sensor.
•  Is the A/F sensor installed securely?
Yes
Go to the next step.
No
Retighten the A/F sensor, then go to Step 26.
(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
12
INSPECT EXHAUST SYSTEM FOR LEAKAGE
•  Visually inspect for exhaust leakage between exhaust manifold and A/F sensor.
•  Is there any leakage?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 26.
No
Replace the A/F sensor, then go to Step 26.
(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
13
INSPECT PURGE CONTROL SYSTEM OPERATION
•  Perform the Purge Control System Inspection.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 26.
No
Go to the next step.
14
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, then go to Step 26.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
No
Go to the next step.
15
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, then go to Step 26.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
No
Go to the next step.
16
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, then go to Step 26.
(See ELECTRIC VARIABLE VALVE TIMING ACTUATOR, HYDRAULIC VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
No
Go to the next step.
17
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, then go to Step 26.
No
Go to the next step.
18
INSPECT FUEL INJECTOR OPERATION
•  Perform the Fuel Injector Operation Inspection.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results, then go to Step 26.
No
Go to the next step.
19
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 23.
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, then go to Step 26.
•  If there is no malfunction:
―  Go to Step 22.
Higher than 3 MPa {31 kgf/cm2, 435 psi}:
•  Go to the next step.
20
IDENTIFY CAUSE BY FUEL PRESSURE SENSOR OR HIGH PRESSURE FUEL PUMP
•  Is the vehicle acceleration performance normal?
Yes
Go to the next step.
No
Go to Step 22.
21
INSPECT FUEL PRESSURE SENSOR
•  Inspect the fuel pressure sensor.
•  Is there any malfunction?
Yes
Replace the fuel distributor, then go to Step 26.
(See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
No
Go to Step 23.
22
INSPECT SPILL VALVE CONTROL SOLENOID VALVE CONTROL CIRCUIT FOR SHORT TO GROUND
•  Switch the ignition to 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
Repair or replace the wiring harness for a possible short to ground, then go to Step 26.
No
Replace the high pressure fuel pump, then go to Step 26.
(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
23
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:
•  405—485 kPa {4.13—4.94 kgf/cm2, 58.8—70.3 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.
Go to Step 26.
24
INSPECT IGNITION SYSTEM OPERATION
•  Perform the Spark Test.
•  Is a strong blue spark visible at each cylinder?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results, then go to Step 26.
25
INSPECT ENGINE COMPRESSION
•  Inspect the engine compression.
•  Are compression pressures within specification?
Specification:
•  Standard: 827 kPa {8.43 kgf/cm2, 120 psi} (300 rpm)
•  Minimum: 661 kPa {6.74 kgf/cm2, 95.9 psi} (300 rpm)
•  Maximum difference between cylinders: 140 kPa {1.43 kgf/cm2, 20.3 psi}
Note
•  Because the SKYACTIV-G 2.0 retards the intake valve closing timing, compression pressure is low.
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results, then go to the next step.
26
VERIFY DTC TROUBLESHOOTING COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Perform the Drive Mode 03 (Variable Valve Timing, A/F Sensor Heater, HO2S Heater, A/F Sensor, HO2S and TWC Repair Verification Drive Mode).
•  Stop the vehicle and access the ON BOARD READINESS TEST to inspect the Drive Mode completion status.
•  Verify the FUEL_EVAL PID changes to yes.
―  If not, perform the Drive Mode 03 (Variable Valve Timing, A/F Sensor Heater, HO2S Heater, A/F Sensor, HO2S and TWC Repair Verification Drive Mode).
•  Perform the Pending Trouble Code Access Procedure.
•  Is the PENDING CODE for this DTC present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the PCM.
Go to the next step.
No
Go to the next step.
27
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [SKYACTIV-G 2.0].)
No
DTC troubleshooting completed.