P0131

DTC P0131, P0151 A/F SENSOR 1

Component Description

The air fuel ratio (A/F) sensor 1 is a planar dual-cell limit current sensor. The sensor element of the A/F sensor 1 is the combination of a
Nearmst concentration cell (sensor cell) with an oxygen-pump cell, which transports ions. It has a heater in the element.
The sensor is capable of precise measurement = 1, but also in the lean and rich range. Together with its control electronics, the sensor outputs a clear, continuous signal throughout a wide range (0.7 < < air).
The exhaust gas components diffuse through the diffusion gap at the electrode of the oxygen pump and Nearmst concentration cell, where they are brought to thermodynamic balance.

An electronic circuit controls the pump current through the oxygen pump cell so that the composition of the exhaust gas in the diffusion gap remains constant at = 1. Therefore, the A/F sensor 1 is able to indicate air/fuel ratio by this pumping of current. In addition, a heater is integrated in the sensor to ensure the required operating temperature of 700 - 800�C (1,292 - 1,472�F).

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

On Board Diagnosis Logic
To judge the malfunction, the diagnosis checks that the A/F signal computed by ECM from the A/F sensor 1 signal is not inordinately low.

On Board Diagnosis Logic:

DTC Confirmation Procedure

NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10.5 V at idle.

WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select "A/F SEN1 (B1)" or "A/F SEN1 (B2)" in "DATA MONITOR" mode with CONSULT-III.
3. Check "A/F SEN1 (B1)" or "A/F SEN1 (B2)" indication.
If the indication is constantly approx. 0 V, go to P0131.
If the indication is not constantly approx. 0V, go to next step.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Turn ignition switch ON.
6. Turn ignition switch OFF and wait at least 10 seconds.
7. Restart engine.
8. Drive and accelerate vehicle to more than 40 km/h (25 MPH) within 20 seconds after restarting engine.
9. Maintain the following conditions for approximately 20 consecutive seconds.

NOTE:
- Keep the accelerator pedal as steady as possible during cruising.
4. � If this procedure is not completed within 1 minute after restarting engine at step 7, return to step
10. Check 1st trip DTC.
11. If 1st trip DTC is displayed, go to P0131.

WITH GST
Follow the procedure "WITH CONSULT-III" above.

Wiring Diagram

BANK 1

Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-III.

CAUTION:
Never use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

BANK 2

Diagnosis Procedure
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body. Refer to Power Supply and Ground Circuit.

OK or NG
OK - GO TO 2.
NG - Repair or replace ground connections.
2.CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect air fuel ratio (A/F) sensor 1 harness connector.

2. Turn ignition switch ON.

3. Check voltage between A/F sensor 1 terminal 3 and ground with
CONSULT-III or tester.

Voltage: Battery voltage

OK or NG
OK - GO TO 4.
NG - GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E12, F3
- IPDM E/R harness connector E7
- 15 A fuse
- Harness for open or short between A/F sensor 1 and fuse
Repair or replace harness or connectors.
4.CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between A/F sensor 1 terminal and ECM terminal as per the following. Refer to Wiring Diagram.

Continuity should exist.

4. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.

Continuity should not exist.

5. Also check harness for short to power.
OK or NG
OK - GO TO 5.
NG - Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK INTERMITTENT INCIDENT
Perform Diagnosis Procedure.
OK or NG
OK - GO TO 6.
NG - Repair or replace malfunctioning part.
6.REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace malfunctioning air fuel ratio (A/F) sensor 1.

CAUTION:
- Discard any A/F 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 A/F sensor, clean exhaust system threads using Oxygen Sensor Thread
Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved Anti-seize Lubricant
(commercial service tool).
INSPECTION END

Removal and Installation

AIR FUEL RATIO (A/F) SENSOR 1
Refer to Component.