Nissan Sentra Service Manual: P1574 ASCD Vehicle speed sensor

Nissan Sentra Service Manual / Engine / Engine control system / Dtc/circuit diagnosis / 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.	Harness or connectors (CAN communication line is open or shorted.) ABS actuator and electric unit (control unit) TCM ECM

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 вЂњABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)вЂќ

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:

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 concern Check the malfunction on the veh ...

Removal and installation
BCM Removal and installation Note: Before replacing BCM, perform вЂњREAD CONFIGURATIONвЂќ to save or print current vehicle specification. Refer to BCS-61, "CONFIGURATION (BCM) : Description". Removal Disconnect the negative battery terminal. Refer to pg-52, "removal a ...

Rear window defogger feedback signal
Description Turns the indicator lamp in the rear window defogger switch ON when operating the rear window defogger. Component function check 1.Check rear window defogger feedback signal Check that the indicator lamp of rear window defogger switch is illuminated when turning the rear window ...