Nissan Murano: Heater & Air Conditioning Control System :: Dtc/circuit Diagnosis / Door Motor Communication Circuit
Diagnosis Procedure
NOTE:
If all of door motor DTCs are detected, check this circuit.
CHECK EACH DOOR MOTOR COMMUNICATION SIGNAL
-
Ignition switch ON.
-
Check output waveform between A/C auto amp. harness connector and ground with the oscilloscope.
| + | − | Output waveform |
| A/C auto amp. |
| Connector | Terminal |
| M50 |
16 |
Ground |

|
Is the inspection result normal?
YES>>
GO TO 2.
NO>>
GO TO 3.
CHECK EACH DOOR MOTOR COMMUNICATION SIGNAL CIRCUIT FOR OPEN
-
Ignition switch OFF.
-
Disconnect A/C auto amp. connector and intake door motor connector.
-
Check continuity between A/C auto amp. harness connector and intake door motor harness connector.
| A/C auto amp. | Intake door motor | Continuity |
| Connector | Terminal | Connector | Terminal |
| M50 |
16 |
M153 |
3 |
Yes |
Is the inspection result normal?
YES>>
Inspection End.
NO>>
Repair harness or connector.
CHECK EACH DOOR MOTOR COMMUNICATION SIGNAL CIRCUIT FOR SHORT
-
Disconnect following connectors:
-
Air mix door motor LH
-
Air mix door motor RH
-
Mode door motor
-
Check continuity between A/C auto amp. harness connector and ground.
| A/C auto amp. | — | Continuity |
| Connector | Terminal |
| M50 |
16 |
Ground |
No |
Is the inspection result normal?
YES>>
Replace A/C auto amp. Refer to Removal and Installation.
NO>>
Repair harness or connector.
Diagnosis Procedure
CHECK EACH DOOR MOTOR POWER SUPPLY
Ignition switch ON.
Check voltage between intake door motor harness connector and ground.
+ −
Voltage
(Approx...
Diagnosis Procedure
CHECK FUSE
Ignition switch OFF.
Check 15A fuses [Nos. 17 and 27, located in fuse block (J/B)].
NOTE:
Refer to Terminal Arrangement
Is the inspection result normal?
YES>>
GO TO 2...
Other information:
DTC Description
DTC DETECTION LOGICWhen the ignition switch is ON, TCM is unable to receive the CAN communications signal from ECM continuously for 2 seconds or more. DTC
CONSULT screen terms
(Trouble diagnosis content)
DTC detection condition
U0100
LOST COMM (ECM A)
(Lost Communication With ECM/PCM A)
Diagnosis condition
When the ignition switch is ON
Signal
CAN communication signal
Threshold
TCM is unable to receive the CAN communications signal from ECM
Diagnosis delay time
Continuously for 2 seconds or more
POSSIBLE CAUSE
ECM
Harness or connector (CAN communication line is open or shorted)
FAIL-SAFE
Selector shock is large
Start is slow
Acceleration is slow
Lock-up is not performed
DTC Confirmation Procedure
CHECK DTC PRIORITY
WhenDTC U0100 is displayed together with DTC U0300, diagnose first the DTC U0300...
The rear center seat belt has a connector
tongue and a seat belt tongue
. Both
the connector tongue and the seat belt
tongue must be securely latched for
proper seat belt operation.
WARNING
Always fasten the connector tongue
and the seat belt in the order shown...