P0031

DTC P0031 HO2S1 HEATER

Description

SYSTEM DESCRIPTION




The ECM performs ON/OFF control of the heated oxygen sensor 1 heaters corresponding to the engine speed.




OPERATION

CONSULT-II Reference Value In Data Monitor Mode:

CONSULT-II Reference Value in Data Monitor Mode

On Board Diagnosis Logic:

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 10.5 V and 16 V at idle.

WITH CONSULT-II




1. Turn ignition switch ON and select "DATA MONITOR" mode with CONSULT-II.
2. Start engine and run it for at least 6 seconds at idle speed.
3. If 1st trip DTC is detected, Go to "Diagnostic Procedure" below.

WITH GST
1. Start engine and run it for at least 6 seconds at idle speed.
2. Turn ignition switch OFF, wait at least 5 seconds and then turn ON.
3. Start engine and run it for at 6 seconds at idle speed.
4. Turn ignition switch OFF, wait at least 5 seconds and then turn ON.
5. Start engine and run it for at 6 seconds at idle speed.
6. Select MODE 3 with GST.
7. If DTC is detected, Go to "Diagnostic Procedure" below.
- When using GST, DTC Confirmation Procedure should be performed twice as much as when using CONSULT-II because GST cannot display MODE 7 (1st trip DTC) concerning this diagnosis. Therefore, using CONSULT-II is recommended.

EC-O2H1B1-01:

EC-O2H1B2-01:

Wiring Diagram

Diagnostic Procedure (Step 1):

Diagnostic Procedure (Steps 2 - 5):

Diagnostic Procedure

Component Inspection

HEATED OXYGEN SENSOR 1 HEATER




1. Check resistance between HO2S1 terminals 3 and 1.

Resistance: 2.3 - 4.3 Ohms at 25 °C (77 °F)

2. Check continuity between HO2S1 terminals 2 and 1, 3 and 2.
Continuity should not exist.

3. If NG, replace heated oxygen sensor 1.

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 J-43897-18 or J-43897-12 and approved anti-seize lubricant.