STEP 1. Using scan tool MB991958, check data list item AD: Heated Oxygen Sensor (rear).
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 AD, Heated Oxygen Sensor (rear).- Transaxle: 2nd speed
- Drive with wide open throttle
- Engine: 3,500 r/min or more
- The output voltages should be between 0.6 and 1.0 volt.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
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 . Go to Step 2.
STEP 2. Measure the sensor output voltage at heated oxygen sensor (rear) connector D-38 by backprobing.
(1) Do not disconnect the connector D-38.
(2) Start the engine and run at idle.
(3) Measure the voltage between terminal No. 3 and ground by backprobing under the following driving.- Transaxle: 2nd speed
- Drive with wide open throttle
- Engine: 3,500 r/min or more
- The output voltage should be between 1.1 and 1.5 volts.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the measured voltage within the specified range?
Go to Step 3. Go to Step 6.
STEP 3. Check harness connector B-26 at ECM for damage.
STEP 4. Measure the sensor output voltage at ECM connector B-26 by using power plant ECU check harness special tool MB992110.
(1) Disconnect all ECM connectors. Connect the power plant ECU check harness special tool MB992110 between the separated connectors.
(2) Start the engine and run at idle.
(3) Measure the voltage between terminal No. 40 and ground under the following driving.- Transaxle: 2nd speed
- Drive with wide open throttle
- Engine: 3,500 r/min or more
- The output voltage should be between 1.1 and 1.5 volts.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the measured voltage between 1.1 and 1.5 volts?
Go to Step 13. Go to Step 5.
STEP 5. Check harness connector D-38 at heated oxygen sensor (rear) for damage.
STEP 6. Check harness connector D-38 at heated oxygen sensor (rear) for damage.
STEP 7. Measure the sensor offset voltage at heated oxygen sensor (rear) harness side connector D-38.
(1) Disconnect the connector D-38 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.
Is the measured voltage between 0.4 and 0.6 volt?
Go to Step 9. Go to Step 8.
STEP 8. Check harness connector B-26 at ECM for damage.
STEP 9. Check harness connector B-26 at ECM for damage.
STEP 10. Check for harness damage between heated oxygen sensor (rear) connector D-38 (terminal No. 4) and ECM connector B-26 (terminal No. 41).
STEP 11. Check for short circuit to ground between heated oxygen sensor (rear) connector D-38 (terminal No. 3) and ECM connector B-26 (terminal No. 40).
STEP 12. Check the heated oxygen sensor (rear).
(1) Disconnect the heated oxygen sensor (rear) connector D-38 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. |
note | 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. |
Is the measured voltage between 0.6 and 1.0 volt?
Go to Step 13. Replace the heated oxygen sensor (rear). Then go to Step 14.
STEP 13. Using scan tool MB991958, check data list item AD: Heated Oxygen Sensor (rear).
STEP 14. 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 22 . (2) Check the diagnostic trouble code (DTC).
Is DTC P0137 set?
Retry the troubleshooting. The inspection is complete.