B2790

B278F, B2790 HEATER PUMP

DTC Logic


DTC DETECTION LOGIC







DTC CONFIRMATION PROCEDURE


1. PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT
1.Turn power switch OFF.
2.Set the vehicle to READY.
3.Select "Self Diagnostic Result" mode of "HVAC" using CONSULT.
4.Check DTC.
Is DTC detected?
YES- Refer to "Diagnosis Procedure" .
NO- INSPECTION END


Diagnosis Procedure


1. INSPECTION START

Confirm the detected DTC. Refer to "DTC Logic" .
Which DTC is detected?
B278F - GO TO 2.
B2790- GO TO 6.

2. CHECK HEATER PUMP COMMUNICATION LINE FOR OPEN

1.Turn power switch OFF.
2.Disconnect heater pump and A/C auto amp. connector.
3.Check continuity between heater pump harness connector and A/C auto amp. harness connector.





Is the inspection result normal?
YES- GO TO 3.
NO- Repair harness or connector.

3. CHECK HEATER PUMP COMMUNICATION LINE FOR SHORT

Check continuity between heater pump harness connector and ground.





Is the inspection result normal?
YES- GO TO 4.
NO- Repair harness or connector.

4. CHECK A/C AUTO AMP. INPUT SIGNAL

1.Connect heater pump and A/C auto amp. connector.
2.Turn power switch ON.
3.Check signal between A/C auto amp. harness connector and ground with oscilloscope.





Is the inspection result normal?
YES- GO TO 5.
NO- Replace A/C control (A/C auto amp.). Refer to "Removal and Installation" Service and Repair.

5. CHECK INTERMITTENT INCIDENT

Check intermittent incident. Refer to "Intermittent Incident" Intermittent Incident.
Is the inspection result normal?
YES- Replace heater pump. Refer to "Removal and Installation" Removal And Installation.
NO- Repair or replace malfunctioning parts.

6. CHECK HEATER PUMP COMMUNICATION LINE FOR OPEN

1.Turn power switch OFF.
2.Disconnect heater pump and A/C auto amp. connector.
3.Check continuity between heater pump harness connector and A/C auto amp. harness connector.





Is the inspection result normal?
YES- GO TO 7.
NO- Repair harness or connector.

7. CHECK HEATER PUMP COMMUNICATION LINE FOR SHORT

Check continuity between heater pump harness connector and ground.





Is the inspection result normal?
YES- GO TO 8.
NO- Repair harness or connector.

8. CHECK A/C AUTO AMP. INPUT SIGNAL

1.Connect heater pump and A/C auto amp. connector.
2.Turn power switch ON.
3.Check signal between A/C auto amp. harness connector and ground with oscilloscope.





Is the inspection result normal?
YES- GO TO 9.
NO- Replace heater pump. Refer to "Removal and Installation" Removal And Installation.

9. CHECK INTERMITTENT INCIDENT

Check intermittent incident. Refer to "Intermittent Incident" Intermittent Incident.
Is the inspection result normal?
YES- Replace A/C control (A/C auto amp.). Refer to "Removal and Installation" Service and Repair.
NO- Repair or replace malfunctioning parts.