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DTC P2097-00: Air-fuel ratio feedback control system too rich
 
 
 
 
TECHNICAL DESCRIPTION
  • The ECM effects air-fuel ratio feedback control in accordance with the signals from the linear air-fuel ratio sensor.
  • If the linear air-fuel ratio sensor has deteriorated, corrections will be made by the heated oxygen sensor (rear).
 
 
DESCRIPTIONS OF MONITOR METHODS
  • When an abnormality exists in the linear air-fuel ratio sensor, the amount of compensated fuel injection is abnormal. When this situation continues, it is judged to be faulty.
  • If an abnormality exists in the heated oxygen sensor (rear), also it is judged to be faulty even though the linear air-fuel ratio sensor is normal.
 
 
MONITOR EXECUTION
Continuous.
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC set in memory for the item monitored below)
  • Linear air-fuel ratio sensor monitor
  • Heated oxygen sensor (rear) monitor
  • Linear air-fuel ratio sensor heater monitor
  • Heated oxygen sensor (rear) heater monitor
  • Heated oxygen sensor offset voltage monitor
  • Misfire monitor
  • Fuel system 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
  • Fuel tank pressure sensor
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
  • Engine coolant temperature is higher than 76°C (169°F).
  • The closed loop air-fuel control continues for 10 seconds or more.
  • More than 70 seconds have passed since the engine starting sequence was completed.
  • Mass airflow sensor output is 13 g/sec (0.39 oz./sec) or more.
  • After the engine start, the accumulated time where the four conditions mentioned above are satisfied is 25 seconds or more.
Judgment Criterion
  • The amount of compensated rich air-fuel ratio is output by the heated oxygen sensor (rear). The status that the amount of compensated rich air-fuel ratio is specified amount continues for 5 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
None.
 
 
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 2 OBD- II DRIVE CYCLE.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
  • Linear air-fuel ratio sensor failed.
  • Heated oxygen sensor (rear) failed.
  • Fuel injector failed.
  • ECM failed.
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
1.STEP 1. Using scan tool (M.U.T.-III SE), read the DTC.
Use scan tool (M.U.T.-III SE) to check and see if a DTC other than P2097-00 is set.
Q: Is DTC other than P2097-00 set?
Perform troubleshooting for the set DTC (Refer to DIAGNOSTIC TROUBLE CODE CHART).
 
2.STEP 2. Test the OBD-II drive cycle after replace the linear air-fuel ratio sensor.
After replacing the linear air-fuel ratio sensor and erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Replace the linear air-fuel ratio sensor (Refer to ENGINE, Engine, Motor and Emission Control – Emission Control – Exhaust Gas Purification System CATALYTIC CONVERTER REMOVAL AND INSTALLATION).
(2) Use scan tool (M.U.T.-III SE) to erase the DTC.
(3) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 2 OBD- II DRIVE CYCLE).
(4) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC P2097-00 set?
The inspection is complete.
 
3.STEP 3. Test the OBD-II drive cycle after replace the heated oxygen sensor (rear).
After replacing the heated oxygen sensor (rear) and erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Replace the heated oxygen sensor (rear) (Refer to ENGINE, Engine, Motor and Emission Control – Emission Control – Exhaust Gas Purification System CATALYTIC CONVERTER REMOVAL AND INSTALLATION).
(2) Use scan tool (M.U.T.-III SE) to erase the DTC.
(3) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 2 OBD- II DRIVE CYCLE).
(4) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC P2097-00 set?
The inspection is complete.
 
4.STEP 4. Test the OBD-II drive cycle after replace the fuel injector.
After replacing the fuel injector and erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Replace the fuel injector (Refer to FUEL INJECTOR REMOVAL AND INSTALLATION).
(2) Use scan tool (M.U.T.-III SE) to erase the DTC.
(3) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 2 OBD- II DRIVE CYCLE).
(4) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC P2097-00 set?
Replace the ECM (Refer to ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION).
The inspection is complete.