DTC DETECTION 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.
DTC No. | Trouble diagnosis name | DTC detecting condition | Possible cause |
P0131 | Air fuel ratio (A/F) sensor 1 circuit low voltage | The A/F signal computed by ECM from the A/F sensor 1 signal is constantly approx. 0 V. |
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DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
TESTING CONDITION: Before performing the following procedure, confirm that battery voltage is more than 10.5 V at idle.
>> GO TO 2.
2.CHECK A/F SENSOR FUNCTION
Is the indication constantly approx. 0 V?
YES >> Go to EC, "Diagnosis Procedure".
NO >> GO TO 3.
3.PERFORM DTC CONFIRMATION PROCEDURE
CAUTION: Always drive vehicle at a safe speed.
NOTE:
4. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC, "Diagnosis Procedure".
NO >> INSPECTION END
1.CHECK GROUND CONNECTION
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace ground connection.
2.CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
Is the inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
>> Repair or replace harness or connectors.
4.CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
4. Check the continuity between A/F sensor 1 harness connector and ground or ECM harness connector and ground.
5. Also check harness for short to power.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
5.CHECK INTERMITTENT INCIDENT
Perform GI, "Intermittent Incident".
Is the inspection result normal?
YES >> GO TO 6.
NO >> Repair or replace.
6.REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace malfunctioning air fuel ratio (A/F) sensor 1. Refer to EM, "Exploded View".
CAUTION:
>> INSPECTION END
Malfunction indicator lamp
Component Function Check
1.CHECK MIL FUNCTION
Turn ignition switch ON.
Make sure that MIL lights up.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Go to EC, "Diagnosis Procedure".
Diagnosis Procedure
1.CHECK DTC
Check that DTC UXXXX is not display ...
U1000 Can comm circuit
Description
CAN (Controller Area Network) is a serial communication line for real-time
application. It is an on-vehicle multiplex
communication line with high data communication speed and excellent malfunction
detection ability.
Many electronic control units are equipped onto a vehicle, and ...