P0175
DTC P0175: System too Rich (bank 2)CAUTION: If DTC P0175 has been set, TCL related DTC U1120 is also set After P0175 has been diagnosed, don't forget to erase DTC U1120.
Fuel Trim Circuit
- Refer to DTC P0202 - Injector Circuit - Cylinder 2, P0204 - Injector Circuit - Cylinder 4, P0206 - Injector Circuit - Cylinder
CIRCUIT OPERATION
- Refer to DTC P0202 - Injector Circuit - Cylinder 2, P0204 - Injector Circuit - Cylinder 4, P0206 - Injector Circuit - Cylinder
TECHNICAL DESCRIPTION
- If a malfunction occurs in the fuel system, the fuel trim value becomes too small.
- The PCM checks whether the fuel trim value is within a specified range.
DESCRIPTIONS OF MONITOR METHODS
Left bank air/fuel learning value (long time fuel trim) and air/fuel feedback integral value (short time fuel trim) are too rich
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Misfire monitor
Sensor (The sensor below is determined to be normal)
- Mass airflow sensor.
- Engine coolant temperature sensor.
- Intake air temperature sensor.
- Barometric pressure sensor.
- Throttle position sensor.
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- Under the closed loop air/fuel ratio control.
- Engine coolant temperature is higher than 77 °C (171 °F)
- Mass airflow sensor output is 8 g/sec or more
Judgment Criteria
- Long-term fuel trim has continued to be lower than -125 percent for 5 seconds or
- Short-term fuel trim has continued to be lower than -74 percent for 5 seconds
Check Conditions
- Under the closed loop air/fuel ratio control.
- Engine coolant temperature is higher than 77 °C (171 °F)
- Mass airflow sensor output is 8 g/sec or less
Judgment Criteria
- Long-term fuel trim has continued to be lower than -125 percent for 5 seconds or
- Short-term fuel trim has continued to be lower than -125 percent for 5 seconds
Check Conditions
- Engine coolant temperature is higher than 77 °C (171 °F)
- Under the closed loop air/fuel ratio control
Judgment Criteria
- Long-term fuel trim has continued to be -125 percent for 5 seconds or
- Short-term fuel trim has continued to be -300 percent for 5 seconds
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 2 - Fuel Trim Monitor. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Mass airflow sensor failed.
- Injector (Number 2, 4, 6) failed.
- Incorrect fuel pressure.
- Engine coolant temperature sensor failed.
- Intake air temperature sensor failed.
- Barometric pressure sensor failed.
- Manifold absolute pressure sensor failed.
- Harness damage in left bank injector circuit or connector damage.
- PCM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Using scan tool MB991958, check data list item 12: Mass Airflow Sensor
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991958 to the data reading mode for item 12, Mass Airflow Sensor.
4. Warm up the engine to normal operating temperature: 80 °C to 95 °C (176 °F to 203 °F)
- When idling, between 2.0 and 6.0 g/sec
- When 2,500 r/min, between 8.0 and 16.0 g/sec
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: YES: Go to Step 2.
NO: Refer to, DTC P0101 - Mass Airflow Circuit Range/Performance Problem, DTC P0102 - Mass Airflow Circuit Low Input, DTC P0103 - Mass Airflow Circuit High Input.
STEP 2. Using scan tool MB991958, check data list item 13: Intake Air Temperature Sensor
1. Turn the ignition switch to the "ON" position.
2. Set scan tool MB991958 to the data reading mode for item 13, Intake Air Temperature Sensor.
- The intake air temperature and temperature shown with the scan tool should approximately match.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 3.
NO: Refer to DTC P0111 - Intake Air Temperature Circuit Range/Performance Problem, DTC P0112 - Intake Air Temperature Circuit Low Input, DTC P0113 - Intake Air Temperature Circuit High Input.
STEP 3. Using scan tool MB991958, check data list item 21: Engine Coolant Temperature Sensor.
1. Turn the ignition switch to the "ON" position.
2. Set scan tool MB991958 to the data reading mode for item 21, Engine Coolant Temperature Sensor.
- The engine coolant temperature and temperature shown with the scan tool should approximately match.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 4.
NO: Refer to DTC P0116 - Engine Coolant Temperature Circuit Range/Performance Problem, DTC P0117 - Engine Coolant Temperature Circuit Low Input, DTC P0118 - Engine Coolant Temperature Circuit High Input.
STEP 4. Using scan tool MB991958, check data list item 25: Barometric Pressure Sensor.
1. Turn the ignition switch to the "ON" position
2. Set scan tool MB991958 to the data reading mode for item 25, Barometric Pressure Sensor
- When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg)
- When altitude is 600 m (1,969 feet), 95 kPa (28.1 in.Hg)
- When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 in.Hg)
- When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 in.Hg)
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 5.
NO: Refer to DTC P2227 - Barometric Pressure Circuit Range/Performance Problem, DTC P2228 - Barometric Pressure Circuit Low Input, DTC P2229 - Barometric Pressure Circuit High Input.
STEP 5. Using scan tool MB991958, check data list item 95: Manifold Absolute Pressure Sensor.
1. Connect scan tool MB991958 to the data link connector
2. Turn the ignition switch to the "ON" position
3. Set scan tool MB991958 to the data reading mode for item 95, Manifold Absolute Pressure Sensor.
- When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg)
- When altitude is 600 m (1,969 feet), 95 kPa (28.1 in.Hg)
- When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 in.Hg)
- When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 in.Hg)
4. Start the engine
- When the engine is idling, 16 - 36 kPa (4.7 - 10.6 in.Hg).
- When the engine is suddenly revved, manifold absolute pressure varies.
5. Turn the ignition switch to the "LOCK" (OFF) position
Q: Is the sensor operating properly?
YES: Go to Step 6.
NO: Refer to DTC P0106 - Manifold Absolute Pressure Circuit Range / Performance Problem, DTC P0107 - Manifold Absolute Pressure Circuit Low Input, DTC P0108 - Manifold Absolute Pressure Circuit High Input.
STEP 6. Check the left bank injector.
1. Disconnect the left bank injector connector B-30, B-27, B-26.
2. Measure the resistance between each injector side connector terminal No. 1 and No. 2
Standard value: 10.5 - 13.5 Ohms [at 20 °C (68 °F)]
Q: Is the measured resistance between 10.5 and 13.5 Ohms [at 20 °C (68 °F)]?
YES: Go to Step 7.
NO: Replace the injector. Then go to Step 9.
STEP 7. Check the fuel pressure.
Refer to On-vehicle Service - Fuel Pressure Test.
Q: Is the fuel pressure normal?
YES: Repair it. Then go to Step 9.
NO: Go to Step 8.
STEP 8. Replace the left bank injector
1. Replace the left bank injector
2. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 2 - Fuel Trim Monitor. OBD-II Drive Cycle Pattern Lists
3. Check the diagnostic trouble code (DTC).
Q: Is DTC P0175 set?
YES: Replace the PCM. Then go to Step 9.
NO: The inspection is complete.
STEP 9. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 2 - Fuel Trim Monitor. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC)
Q: Is DTC P0175 output?
YES: Retry the troubleshooting.
NO: The inspection is complete.