P0161

SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the rear heated oxygen sensor heaters corresponding to the engine speed.

OPERATION
Engine speed rpm Rear heated oxygen sensor heaters
Above 3,200 OFF
Below 3,200 ON




CONSULT Reference Value in Data Monitor Mode
Specification data are reference values.




ECM Terminals and Reference Value
Specification data are reference values and are measured between each terminal and 32 (ECM ground).




On Board Diagnosis Logic

DTC Confirmation Procedure

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is between 10.5V and 16V at idle.

With CONSULT
1. Turn ignition switch "ON" and select "DATA MONITOR" mode with CONSULT.
2. Start engine.
3. Drive vehicle at a speed of more than 70 kph (43 MPH) for 2 consecutive minutes.




4. Stop vehicle and let engine idle for at least 6 seconds.
5. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

With GST
1. Start engine.
2. Drive vehicle at a speed of more than 70 kph (43 MPH) for 2 consecutive minutes.
3. Stop vehicle and let engine idle for at least 6 seconds.
4. Turn ignition switch "OFF" and wait at least 5 seconds.
5. Start engine.
6. Drive vehicle at a speed of more than 70 kph (43 MPH) for 2 consecutive minutes.
7. Stop vehicle and let engine idle for at least 6 seconds.
8. Select "MODE 3" with GST.
9. If DTC is detected, go to "Diagnostic Procedure" below.

Without Scan Tool
1. Start engine.
2. Drive vehicle at a speed of more than 70 kph (43 MPH) for 2 consecutive minutes.
3. Stop vehicle and let engine idle for at least 6 seconds.
4. Turn ignition switch "OFF", wait at least 5 seconds and then turn "ON".
5. Perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.
6. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.
- When using GST, "DTC Confirmation Procedure" should be performed twice as much as when using CONSULT or ECM (Diagnostic Test Mode II) because GST cannot display MODE 7 (1st trip DTC) concerning this diagnosis. Therefore, using CONSULT or ECM (Diagnostic Test Mode II) is recommended.

Wiring Diagram LEFT BANK

EC-RO2H-L-01:

EC-RO2H-L-01 Connectors View:

Diagnostic Procedure

Step 1:

Step 2:

Step 3:

Step 4:

Step 5:

Step 6:

Component Inspection




REAR HEATED OXYGEN SENSOR HEATER
Check the following.
1. Check resistance between terminals 2 and 3.
Resistance: 2.3 - 4.3 (ohms) at 25 °C (77 °F)

2. Check continuity.

Terminal No.: Continuity
2 and 1, 3, 4: No
3 and 1, 2, 4: No

If NG, replace the rear heated oxygen sensor.

CAUTION:
- Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool J43897-18 or J-43897-12 and approved anti-seize lubricant.