Nissan Murano: Dtc/circuit Diagnosis / U1040 Eng Comm Circuit
DTC Description
DTC DETECTION LOGIC
When ECM unable to transmit engine communication signal.
| DTC |
CONSULT screen terms
(Trouble diagnosis content) |
DTC detection condition |
| U1040 |
Engine communication line |
Diagnosis condition |
Ignition switch ON |
| Signal (terminal) |
Engine communication signal |
| Threshold |
ECM unable to transmit engine communication signal |
| Diagnosis delay time |
— |
POSSIBLE CAUSE
FAIL-SAFE
| Engine operating condition in fail-safe mode |
| Fail safe mode | Nissan Murano Vehicle behavior |
| Engine communication line |
ECM operates active grille shutter to fully-open position. |
DTC Confirmation Procedure
PRECONDITIONING
If another DTC Confirmation Procedure is conducted just before this procedure, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.
>>
GO TO 2.
PERFORM DTC CONFIRMATION PROCEDURE
-
Turn ignition switch ON and wait at least 10 seconds.
-
Check 1st trip DTC.
Is 1st trip DTC detected?
YES>>
Proceed to Diagnosis Procedure.
NO>>
To check malfunction symptom before repair: Refer to Intermittent Incident.
NO>>
Confirmation after repair: INSPECTION END
Diagnosis Procedure
CHECK ACTIVE GRILLE SHUTTER SIGNAL CIRCUIT
-
Turn ignition switch OFF.
-
Disconnect ECM harness connector.
-
Disconnect active grille shutter harness connector.
-
Check the continuity between ECM harness connector and active grille shutter harness connector.
| + | − | Continuity |
| ECM | Active grille shutter |
| Connector | Terminal | Connector | Terminal |
| F79 |
99 |
E238 |
3 |
Existed |
-
Also check harness for short to ground and short to power.
Is the inspection result normal?
YES>>
INSPECTION END
NO>>
Repair or replace error-detected parts.
DTC Description
DTC DETECTION LOGICWhen ECM cannot receive the engine communication signal from active grille shutter. DTC
CONSULT screen terms
(Trouble diagnosis content)
DTC detection condition
U0284
LOST COMM (A/GRLL SHTTR MDL A)
(Lost communication with active grille air shutter module A)
Diagnosis condition
Ignition switch ON
Signal (terminal)
Engine communication signal
Threshold
ECM cannot receive the engine communication signal from active grille shutter
Diagnosis delay time
—
POSSIBLE CAUSE
Harness and connectors (Engine communication line is open or circuit shorted...
DTC Description
DTC DETECTION LOGICA signal voltage of LIN communication between ECM and generator is excessively low or excessively high. DTC
CONSULT screen terms
(Trouble diagnosis content)
DTC detection condition
U1044
ENG COMM CIRCUIT
(Engine communication circuit)
Diagnosis condition
Ignition switch ON
Signal (terminal)
Signal voltage of LIN communication
Threshold
Signal voltage between ECM and generator is excessively low or excessively high
Diagnosis delay time
—
POSSIBLE CAUSE
Harness or connectors
(LIN communication circuit is open or shorted...
Other information:
Vent
Headlight/fog light (if so equipped)/turn signal switch
Supplemental air bagHorn
Meters and gaugesWarning and indicator lights
Vehicle information display
Wiper and washer switchRear window wiper and washer switch
Audio system/Center display controls
Hazard warning flasher switch
Center displayNavigation display (if so equipped)
Front passenger supplemental air bag
Glove box
Passenger supplemental knee air bag
Front passenger air bag status light
Power outlet
USB portsAUX jack
Heater and air conditioning
controls
Shift lever
Push-button ignition switch
Cruise control switches (if so equipped)Intelligent Cruise Control (ICC)
switches (if so equipped)
Driver supplemental knee air bag
Bluetooth® Hands-Free Phone System/Audio control switches
Hood releaseFuel door release
Fuse box
Heated steering wheel switch (if so equipped)Dynamic driver assistance
switch (if so equipped)
Liftgate instrument panel switch (if so equipped)
24...
The Loose Fuel Cap warning message appears
in the vehicle information display
when the fuel-filler cap is not tightened
correctly after the vehicle has been refueled.
It may take a few driving trips for the
message to be displayed. To turn off the
warning message, perform the following:
Remove and install the fuel-filler cap as
soon as possible...