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DTC P014C-00: Linear air-fuel ratio sensor slow response - Rich to Lean
 
 
 
 
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 the average of the difference between the response times of the rich side and the lean side of the linear air-fuel ratio sensor during the monitoring time becomes equal to or higher than the predetermined value, the DTC is set as the linear air-fuel ratio sensor deterioration.
 
 
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 heater 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 speed is between 1,094 and 3,500 r/min.
  • Volumetric efficiency is between 35 and 85 percent.
  • Mass airflow sensor output is 1.3 g/sec (0.046 oz./sec) or more.
  • Engine coolant temperature is more than 60°C (140°F).
  • Under the closed loop air-fuel control.
  • The accelerator pedal is depressed.
  • Short-term fuel trim is between –25 and +25 percent.
  • More than 8 seconds have passed after the above mentioned conditions have been met.
  • During the drive cycle, the ECM performs monitoring with the accumulated total time of 10 seconds, 3 times.
Judgment Criteria
  • The average response time ratio (to lean time/to rich time) is more than specified value.
  • The amount of compensated air-fuel ratio based on the heated oxygen sensor (rear) is out of specified amount.
 
 
FAIL-SAFE AND BACKUP FUNCTION
None.
 
 
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 5 OBD- II DRIVE CYCLE.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
Linear air-fuel ratio sensor 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. Test the OBD-II drive cycle.
After erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Use scan tool (M.U.T.-III SE) to erase the DTC.
(2) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 5 OBD- II DRIVE CYCLE).
(3) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC P014C-00 set?
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).
Intermittent malfunction (Refer to GENERAL INFORMATION, General Information – How to Use Troubleshooting/Inspection Service Points – How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).