DTC Logic
DTC DETECTION LOGIC
The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/ F) sensor 1. The oxygen storage capacity of the three way catalyst (manifold) causes the longer switching time.
MALFUNCTION A
To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the voltage is unusually high during the various driving condition such as fuel-cut.
MALFUNCTION B
To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the minimum voltage of sensor is sufficiently low during the various driving condition such as fuel-cut.
DTC No. | CONSULT screen terms (Trouble diagnosis content) | DTC detecting condition | Possible cause | |
P0138 | HO2S2 (B1) (O2 sensor circuit high voltage bank 1 sensor 2) | A) | An excessively high voltage from the sensor is sent to ECM. |
|
B) | The minimum voltage from the sensor is not reached to the specified voltage. |
|
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A
Is 1st trip DTC detected? YES >> Proceed to EC-227, "Diagnosis Procedure".
NO-1 ( With CONSULT)>>GO TO 3.
NO-2 ( Without CONSULT)>>GO TO 5.
3.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B
NOTE:
For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30°C (32 to 86°F).
If not, warm up engine and go to next step when “COOLANT TEMP/S” indication reaches 70°C (158°F).
NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.
Which is displayed on CONSULT
OK >> INSPECTION END
NG >> Proceed to EC-227, "Diagnosis Procedure".
CAN NOT BE DIAGNOSED>>GO TO 4.
4.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B AGAIN
>> GO TO 3.
5.PERFORM COMPONENT FUNCTION CHECK FOR MALFUNCTION B
Perform component function check. Refer to EC-226, "Component Function Check".
NOTE:
Use component function check to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st trip DTC might not be confirmed.
Is the inspection result normal? YES >> INSPECTION END
NO >> Proceed to EC-227, "Diagnosis Procedure".
Component Function Check
1.PERFORM COMPONENT FUNCTION CHECK-1
Without CONSULT
Is the inspection result normal? YES >> INSPECTION END
NO >> GO TO 2.
2.PERFORM COMPONENT FUNCTION CHECK-2
Check the voltage between ECM harness connector and ground as per the following condition.
Is the inspection result normal? YES >> INSPECTION END
NO >> GO TO 3.
3.PERFORM COMPONENT FUNCTION CHECK-3
Check the voltage between ECM harness connector and ground as per the following condition.
Is the inspection result normal? YES >> INSPECTION END
NO >> Proceed to EC-227, "Diagnosis Procedure".
Diagnosis Procedure
1.INSPECTION START
Confirm the detected malfunction (A or B). Refer to EC-225, "DTC Logic".
Which malfunction is detected? A >> GO TO 2.
B >> GO TO 6.
2.CHECK HO2S2 CONNECTOR FOR WATER
Water should not exist.
Is the inspection result normal? YES >> GO TO 3.
NO >> Repair or replace error-detected parts.
3.CHECK HO2S2 GROUND CIRCUIT
Is the inspection result normal? YES >> GO TO 4.
NO >> Repair or replace error-detected parts.
4.CHECK HO2S2 INPUT SIGNAL CIRCUIT
Is the inspection result normal? YES >> GO TO 5.
NO >> Repair or replace error-detected parts.
5.CHECK HEATED OXYGEN SENSOR 2
Check the heated oxygen sensor 2. Refer to EC-229, "Component Inspection (HO2S2)".
Is the inspection result normal? YES >> Check intermittent incident. Refer to GI-39, "Intermittent Incident".
NO >> Replace heated oxygen sensor 2. Refer to EX-5, "Exploded View".
6.CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE
Is the 1st trip DTC P0172 detected? Is it difficult to start engine? YES >> Perform trouble diagnosis for DTC P0172. Refer to EC-250, "DTC Logic".
NO >> GO TO 7.
7.CHECK HO2S2 GROUND CIRCUIT
Is the inspection result normal? YES >> GO TO 8.
NO >> Repair or replace error-detected parts.
8.CHECK HO2S2 INPUT SIGNAL CIRCUIT
Is the inspection result normal? YES >> GO TO 9.
NO >> Repair open circuit or short to ground or short to power in harness or connectors.
9.CHECK HEATED OXYGEN SENSOR 2
Check the heated oxygen sensor 2. Refer to EC-229, "Component Inspection (HO2S2)".
Is the inspection result normal? YES >> Check intermittent incident. Refer to GI-39, "Intermittent Incident".
NO >> Replace heated oxygen sensor 2. Refer to EX-5, "Exploded View".
Component Inspection (HO2S2)
1.INSPECTION START
Do you have CONSULT? Do you have CONSULT? YES >> GO TO 2.
NO >> GO TO 3.
2.CHECK HEATED OXYGEN SENSOR 2
With CONSULT
“HO2S2 (B1)” should be above 0.72 V at least once when the “FUEL INJECTION” is + 25%.
“HO2S2 (B1)” should be below 0.18 V at least once when the “FUEL INJECTION” is − 25%.
Is the inspection result normal? YES >> INSPECTION END
NO >> Replace heated oxygen sensor 2. Refer to EX-5, "Exploded View".
3.CHECK HEATED OXYGEN SENSOR 2-1
Without CONSULT
Is the inspection result normal? YES >> INSPECTION END
NO >> GO TO 4.
4.CHECK HEATED OXYGEN SENSOR 2-2
Check the voltage between ECM harness connector and ground as per the following condition.
Is the inspection result normal? YES >> INSPECTION END
NO >> GO TO 5.
5.CHECK HEATED OXYGEN SENSOR 2-3
Check the voltage between ECM harness connector and ground as per the following condition.
Is the inspection result normal? YES >> INSPECTION END
NO >> Replace heated oxygen sensor 2. Refer to EX-5, "Exploded View".
System
EPS system
EPS SYSTEM : System Description
SYSTEM DIAGRAM
DESCRIPTION
EPS control unit performs an arithmetical operation on data,
such
as steering wheel turning force (sensor signal) from the torque
sensor, vehicle speed signal, etc. Then it generates an optimum
assist torque ...
Basic inspection
Diagnosis and repair workflow
Work Flow
OVERALL SEQUENCE
DETAILED FLOW
1. OBTAIN INFORMATION ABOUT SYMPTOM
Interview the customer to obtain as much information as possible about the
conditions and environment under
which the malfunction occurred.
>> GO TO 2.
2. CONFIRM THE SYMPTO ...
Diagnosis system [abs actuator and electric unit (control
unit)]
CONSULT Function (ABS)
FUNCTION
CONSULT can display each diagnostic item using the following
direct diagnostic modes.
Direct Diagnostic Mode
Description
ECU identification
The ABS actuator and electric unit (control unit) part number is
displayed.
Self Diagnos ...