Nissan Sentra Service Manual: P1574 ASCD Vehicle speed sensor
Description
The ECM receives two vehicle speed sensor signals via CAN communication line. One is sent from combination meter, and the other is from TCM (Transmission control module). The ECM uses these signals for ASCD control. Refer to EC-51, "AUTOMATIC SPEED CONTROL DEVICE (ASCD) : System Description" for ASCD functions.
DTC Logic
DTC DETECTION LOGIC
NOTE:
- If DTC P1574 is displayed with DTC U1001, first perform the trouble diagnosis for DTC U1001. Refer to EC-168, "DTC Logic".
- If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500. Refer to EC-330, "EXCEPT FOR M/T MODELS : DTC Logic".
- If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer to EC-348, "DTC Logic".
- If DTC P1574 is displayed with DTC P0607, first perform the trouble diagnosis for DTC P0607. Refer to EC-350, "DTC Logic".
| DTC No. | CONSULT screen terms (Trouble diagnosis content) | DTC detecting condition | Possible cause |
| P1574 | ASCD VHL SPD SEN (ASCD VHL SPD SEN) | ECM detects a difference between two vehicle speed signals is out of the specified range. |
|
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
- Turn ignition switch OFF and wait at least 10 seconds.
- Turn ignition switch ON.
- Turn ignition switch OFF and wait at least 10 seconds.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
- Start engine.
- Drive the vehicle at more than 40 km/h (25 MPH).
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
This procedure may be conducted with the drive wheels lifted in the shop or by driving the vehicle.
If a road test is expected to be easier, it is unnecessary to lift the vehicle.
- Check DTC.
Is DTC detected? YES >> Proceed to EC-397, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis Procedure
1.CHECK DTC WITH TCM
Check DTC with TCM. Refer to TM-108, "CONSULT Function".
Is DTC detected?
NO >> GO TO 2.
YES >> Perform trouble shooting relevant to DTC indicated.
2.CHECK DTC WITH “ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)”
Check DTC with ABS actuator and electric unit (control unit). Refer to BRC-31, "CONSULT Function (ABS)".
Is DTC detected? NO >> INSPECTION END
YES >> Perform trouble shooting relevant to DTC indicated.
P1572 ASCD Brake switch
DTC Logic
DTC DETECTION LOGIC
NOTE:
If DTC P1572 is displayed with DTC P0605, first perform the trouble
diagnosis for DTC P0605. Refer
to EC-348, "DTC Logic".
This self-diagnosi ...
P1650 Starter motor relay 2
Description
ECM controls ON/OFF state of the starter relay, according to the engine and
vehicle condition. ECM transmits
a control signal to IPDM E/R via BCM by CAN communication.
Under normal ...
Other materials:
Garage Jack and Safety Stand and 2-Pole Lift
WARNING:
Park the vehicle on a level surface when using the jack. Make
sure to avoid damaging pipes, tubes,
etc. under the vehicle.
Never get under the vehicle while it is supported only by the
jack. Always use safety stands when
you have to get under the vehicle.
Place wheel chock ...
Precaution for Work
When removing or disassembling each component, be careful not to damage
or deform it. If a component
may be subject to interference, be sure to protect it with a shop cloth.
When removing (disengaging) components with a screwdriver or similar
tool, be sure to wrap the component
with a ...
Eps branch line circuit
Diagnosis procedure
1.Check connector
Turn the ignition switch off.
Disconnect the battery cable from the negative terminal.
Check the terminals and connectors of the eps control unit for damage,
bend and loose connection (unit
side and connector side).
Is the inspection result norm ...
