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DTC P2252: Heated Oxygen Sensor Offset Circuit Low Voltage
 
 
 
 
HEATED OXYGEN SENSOR OFFSET CIRCUIT LOW VOLTAGE CIRCUIT
Refer to DTC P0137 - Heated Oxygen Sensor (rear) Circuit Low Voltage .
 
 
CIRCUIT OPERATION
Refer to DTC P0137 - Heated Oxygen Sensor (rear) Circuit Low Voltage .
 
 
TECHNICAL DESCRIPTION
  • The ECM applies an offset voltage of 0.5 volt to the heated oxygen sensor.
  • The ECM checks for heated oxygen sensor offset voltage.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • Heated oxygen sensor offset voltage is under specified range.
 
 
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)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
DTC SET CONDITION
Logic Flow Chart
 
 
Check Condition
  • More than 2 seconds have passed since the power supply mode of the electric motor switch was ON.
Judgment Criterion
  • Heated oxygen sensor offset voltage is lower than 0.4 volt for 2 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • None.
 
 
OBD-II DRIVE CYCLE PATTERN
  • Refer to Diagnosis Function - OBD-II Drive Cycle - Pattern 1 .
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
  • Heated oxygen sensor (rear) failed.
  • Shorted heated oxygen sensor (rear) circuit or connector damage.
  • ECM failed.

 
 
DIAGNOSIS
Required Special Tool:
  • MB991658: Test Harness
STEP 1. Check the heated oxygen sensor (rear).
(1) Disconnect the heated oxygen sensor (rear) connector and connect test harness special tool MB991658 to the connector on the heated oxygen sensor (rear) side.
(2) Set the vehicle to the continuous idling mode.
(3) Warm up the engine until engine coolant temperature reaches 80°C (176°F) or higher.
(4) Rev the engine for 5 minutes or more with the engine speed of 2,000 r/min.
(5) Connect a digital voltage meter between terminal O2RL and terminal ORLE.
(6) While repeatedly revving the engine, measure the heated oxygen sensor (rear) output voltage.
(7)
Standard value: 0.6 - 1.0 V
noteIf the temperature of sensing area does not reach the high temperature [of approximately 400°C (752°F) or more] even though the heated oxygen sensor is normal, the output voltage would be possibly low in spite of the rich air-fuel ratio.
noteWhen the vehicle is driven with high loads, the temperature of the sensing area of the heated oxygen sensor is sufficiently high. Thus, it is not necessary to apply the voltage to the heater.
Is the measured voltage between 0.6 and 1.0 volt?
Go to Step 2.
Replace the heated oxygen sensor (rear). Then go to Step 5.
 
STEP 2. Measure the sensor offset voltage at heated oxygen sensor (rear) harness side connector.
(1) Disconnect the heated oxygen sensor (rear) connector and measure at the harness side.
(2) Turn on the power supply mode of the electric motor switch.
(3) Measure the voltage between terminal ORLE and ground.
  • Voltage should be between 0.4 and 0.6 volt.
(4) Turn off the power supply mode of the electric motor switch.
Is the measured voltage between 0.4 and 0.6 volt?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check of short circuit to ground in ORLE line between heated oxygen sensor (rear) connector and ECM connector.
Is the harness wire in good condition?
Go to Step 4.
Repair the connector(s) or wiring harness. Then go to Step 5.
 
STEP 4. Check the trouble symptoms.
(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P2252 set?
Replace the ECM (Refer to Removal and Installation ). Then go to Step 5.
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/ Inspection Service Points - How to Cope with Intermittent Malfunctions .
 
STEP 5. 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 - Pattern 1 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P2252 set?
Retry the troubleshooting.
The inspection is complete.