P2A00

P2A00 A/F Sensor 1

Component Description

The 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 Nernst 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 Nernst 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).





On Board Diagnosis Logic

To judge the malfunction, the A/F signal computed by ECM from the air fuel ratio (A/F) sensor 1 signal is monitored not to be shifted to LEAN side or RICH side.






DTC Confirmation Procedure

NOTE:

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

with SDT

1 Start engine and warm it up to normal operating temperature.
2 Turn ignition switch OFF and wait at least 10 seconds.
3 Turn ignition switch ON and select "SELF-LEARNING CONT" in "Utility" mode with SDT.
4 Clear the self-learning coefficient by touching "CLEAR".
5 Turn ignition switch OFF and wait at least 10 seconds.
6 Start engine and keep the engine speed between 3,500 and 4,000 rpm for 1 minute under no load.
7 Let engine idle for 1 minute.
8 Keep engine speed between 2,500 and 3,000 rpm for 20 minutes.
9 Check 1st trip DTC.
10 If 1st trip DTC is detected, go to "Diagnosis Procedure".

with GST

1 Start engine and warm it up to normal operating temperature.
2 Turn ignition switch OFF and wait at least 10 seconds.
3 Disconnect mass air flow sensor harness connector.





4 Start engine and let it idle for at least 5 seconds.
5 Stop engine and reconnect mass air flow sensor harness connector.
6 Select Service $03 with GST and make sure that DTC P0102 is detected.
7 Select Service $04 with GST and erase the DTC P0102.
8 Start engine and keep the engine speed between 3,500 and 4,000 rpm for 1 minute under no load.
9 Let engine idle for 1 minute.
10 Keep engine speed between 2,500 and 3,000 rpm for 20 minutes.
11 Select Service $07 with GST.
If 1st trip DTC is detected, go to "Diagnosis Procedure".

Diagnosis Procedure

1. CHECK GROUND CONNECTIONS

1 Turn ignition switch OFF.
2 Loosen and retighten two ground screws on the body. Refer to [Power Supply and Ground Circuit Check] Power Supply and Ground Circuit Check.






OK or NG
OK
GO TO 2.
NG
Repair or replace ground connections.

2. RETIGHTEN AIR FUEL RATIO (A/F) SENSOR 1 AND HEATED OXYGEN SENSOR 2

Loosen and retighten the air fuel ratio (A/F) sensor 1 and heated oxygen sensor 2. Refer to [Engine Control Component Parts Location] Locations.


GO TO 3.

3. CHECK FOR EXHAUST GAS LEAK

1 Start engine and run it at idle.
2 Listen for an exhaust gas leak before the three way catalyst 2.

Is exhaust gas detected?
YES
Repair or replace.
NO
GO TO 4.

4. CHECK FOR INTAKE AIR LEAK

1 Start engine and run it at idle.
2 Listen for an intake air leak after the mass air flow sensor.

OK or NG
OK
GO TO 5.
NG
Repair or replace.

5. CLEAR THE SELF-LEARNING DATA.

With SDT
1 Start engine and warm it up to normal operating temperature.
2 Select "SELF-LEARNING CONT" in "Utility" mode with SDT.
3 Clear the self-learning control coefficient by touching "CLEAR".
4 Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171 or P0172 detected?
Is it difficult to start engine?
Without SDT
1 Start engine and warm it up to normal operating temperature.
2 Turn ignition switch OFF.
3 Disconnect mass air flow sensor harness connector.





4 Restart engine and let it idle for at least 5 seconds.
5 Stop engine and reconnect mass air flow sensor harness connector.
6 Make sure DTC P0102 is displayed.
7 Erase the DTC memory. Refer to [On Board Diagnosis Function] On Board Diagnosis Function (Without SDT) or [SDT Function] SDT Function (With SDT).
8 Make sure DTC P0000 is displayed.
9 Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171 or P0172 detected?
Is it difficult to start engine?

Yes or No
Yes
Perform trouble diagnosis for DTC P0171 or P0172. Refer to [P0031, P0032 A/F Sensor 1 Heater] P0171 or P0172.
No
GO TO 6.

6. CHECK HARNESS CONNECTOR

1 Turn ignition switch OFF.
2 Disconnect A/F sensor 1 harness connector.





3 Check harness connector for water.






OK or NG
OK
GO TO 7.
NG
Repair or replace harness connector.

7. CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT

1 Turn ignition switch ON.





2 Check voltage between A/F sensor 1 terminal 3 and ground with SDT or tester.











OK or NG
OK
GO TO 9.
NG
GO TO 8.

8. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors E2, F32
- IPDM E/R harness connector E119
- 10 A fuse
- Harness for open or short between A/F sensor 1 and fuse


Repair or replace harness or connectors.

9. 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 the following terminals. Refer to Wiring Diagram.










4 Check harness continuity between ECM terminals 16, 35, 56, 75 or A/F sensor 1 terminals 1, 2, 5, 6 and ground. Refer to Wiring Diagram.






5 Also check harness for short to power.

OK or NG
OK
GO TO 10.
NG
Repair open circuit, short to ground or short to power in harness or connectors.

10. CHECK A/F SENSOR 1 HEATER

Refer to P0031.

OK or NG
OK
GO TO 11.
NG
GO TO 13.

11. CHECK HEATED OXYGEN SENSOR 2

Refer to [P0137 HO2S2] P0137.

Is the inspection result normal?
YES
GO TO 12.
NO
Replace heated oxygen sensor 2. Refer to [Engine Control Component Parts Location] Locations.

12. CHECK INTERMITTENT INCIDENT

Perform [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.

OK or NG
OK
GO TO 13.
NG
Repair or replace.

13. REPLACE AIR FUEL RATIO (A/F) SENSOR 1

Replace air fuel ratio (A/F) sensor 1. Refer to [Exhaust Manifold and Three Way Catalyst: Exploded View [QR25DE] Exhaust Manifold and Three Way Catalyst Exploded View ].

CAUTION:
- Discard any air fuel ratio (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 air fuel ratio (A/F) sensor, clean exhaust system threads using Heated Oxygen Sensor Thread Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant (commercial service tool).


GO TO 14.

14. CONFIRM A/F ADJUSTMENT DATA

1 Turn ignition switch ON.
2 Select "A/F ADJ-B1" in "Data list" mode with SDT.
3 Make sure that "0.000" is displayed on SDT screen.

OK or NG
OK
INSPECTION END.
NG
GO TO 15.

15. CLEAR THE SELF-LEARNING DATA

With SDT
1 Start engine and warm it up to normal operating temperature.
2 Select "SELF-LEARNING CONT" in "Utility" mode with SDT.
3 Clear the self-learning control coefficient by touching "CLEAR".
Without SDT
1 Start engine and warm it up to normal operating temperature.
2 Turn ignition switch OFF.
3 Disconnect mass air flow sensor harness connector.





4 Restart engine and let it idle for at least 5 seconds.
5 Stop engine and reconnect mass air flow sensor harness connector.
6 Make sure DTC P0102 is displayed.
7 Erase the DTC memory. Refer to [On Board Diagnosis Function] On Board Diagnosis Function (Without SDT) or [SDT Function] SDT Function (With SDT).
8 Make sure DTC P0000 is displayed.


GO TO 16.

16. CONFIRM A/F ADJUSTMENT DATA

1 Turn ignition switch OFF and then ON.
2 Select "A/F ADJ-B1" in "Data list" mode with SDT.
3 Make sure that "0.000" is displayed on SDT screen.


INSPECTION END