Except For California

DTC P2252: Heated Oxygen Sensor Offset Circuit Low Voltage [Except vehicles for California]










HEATED OXYGEN SENSOR OFFSET CIRCUIT LOW VOLTAGE CIRCUIT
Refer to DTC P0137 - Heated Oxygen Sensor (rear) Circuit Low Voltage [Except vehicles for California]. Except Vehicles For California

CIRCUIT OPERATION
Refer to DTC P0137 - Heated Oxygen Sensor (rear) Circuit Low Voltage [Except vehicles for California]. Except Vehicles For California

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 stored in memory for the item monitored below)
- Not applicable

Sensor (The sensor below is determined to be normal)
- Not applicable

DTC SET CONDITION







Check Condition
- More than 2 seconds have passed since the engine starting sequence was completed.

Judgement Criterion
- Heated oxygen sensor offset voltage is less 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 23. OBD- II Drive Cycle

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 Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
- MB991658: Test Harness

STEP 1. Check harness connector D-40 at heated oxygen sensor (rear) for damage.

Q: Are the harness connectors in good condition?

YES : Go to Step 2.

NO : Repair or replace them. Then go to Step 7.

STEP 2. Check the heated oxygen sensor (rear).

1. Disconnect the heated oxygen sensor (rear) connector D-40 and connect test harness special tool MB991658 to the connector on the heated oxygen sensor (rear) side.
2. Warm up the engine until engine coolant temperature reaches 80 °C (176 °F) or higher.
3. Drive at 50 km/h (31mph) or more for 10 minutes.







4. Connect a digital voltage meter between terminal No. 3 and terminal No. 4.
5. Measure the output voltage of heated oxygen sensor under the following driving.
- Transaxle: 2nd speed
- Drive with wide open throttle
- Engine: 3,500 r/min or more

Standard value: 0.6 - 1.0 V

NOTE:
- If 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.
- When 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.

Q: Is the measured voltage between 0.6 and 1.0 volt?

YES : Go to Step 3.

NO : Replace the heated oxygen sensor (rear). Then go to Step 7.

STEP 3. Measure the sensor offset voltage at heated oxygen sensor (rear) harness side connector D-40.

1. Disconnect the connector D-40 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.







3. Measure the voltage between terminal No. 4 and ground.
- Voltage should be between 0.4 and 0.6 volt.

4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the measured voltage between 0.4 and 0.6 volt?

YES : Go to Step 6.

NO : Go to Step 4.

STEP 4. Check harness connector B-108 at ECM for damage.

Q: Is the harness connector in good condition?

YES : Go to Step 5.

NO : Repair or replace it. Then go to Step 7.

STEP 5. Check for short circuit to ground between heated oxygen sensor (rear) connector D-40 (terminal No. 4) and ECM connector B-108 (terminal No. 41).

NOTE: Check harness after checking intermediate connectors A-10 and C-37. If intermediate connectors are damaged, repair or replace them. Then go to Step 7.

Q: Is the harness wire in good condition?

YES : Go to Step 6.

NO : Repair it. Then go to Step 7.

STEP 6. Check the trouble symptoms.

1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD- II Drive Cycle
2. Check the diagnostic trouble code (DTC).

Q: Is DTC P2252 set?

YES : Replace the ECM. Then go to Step 7.

NO : It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions. Troubleshooting Contents

STEP 7. 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 23. OBD- II Drive Cycle
2. Check the diagnostic trouble code (DTC).

Q: Is DTC P2252 set?

YES : Retry the troubleshooting.

NO : The inspection is complete.