Nissan Sentra. Manual - part 425

EC-396

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

P1572 ASCD BRAKE SWITCH

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace stop lamp switch. Refer to 

BR-22, "Exploded View"

.

P1574 ASCD VEHICLE SPEED SENSOR

EC-397

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

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P1574 ASCD VEHICLE SPEED SENSOR

Description

INFOID:0000000009758650

The ECM receives two vehicle speed sensor signals via CAN communication line. One is sent from combina-

tion 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

INFOID:0000000009758651

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 CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting the next test.

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

3. Turn ignition switch OFF and wait at least 10 seconds.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1. Start engine.

2. 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.

3. Check DTC.
Is DTC detected?

YES

>> Proceed to 

EC-397, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000009758652

1.

CHECK DTC WITH TCM

Check DTC with TCM. Refer to 

TM-108, "CONSULT Function"

.

Is DTC detected?

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 speci-
fied range.

• Harness or connectors

(CAN communication line is open or shorted.)

• ABS actuator and electric unit (control unit)
• TCM
• ECM

EC-398

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

P1574 ASCD VEHICLE SPEED SENSOR

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.

P1650 STARTER MOTOR RELAY 2

EC-399

< DTC/CIRCUIT DIAGNOSIS >

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P1650 STARTER MOTOR RELAY 2

Description

INFOID:0000000009758653

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 conditions, ECM controls and maintains the starter relay in OFF state during following condition: 

• Engine is running.

• Selector lever is D position.

When detecting a decrease in engine speed due to rapid deceleration or heavy load condition, ECM controls

and reactivates the starter relay.

IPDM E/R detects a control state of starter relay and starter control relay and transmits a feedback signal to

ECM via CAN communication.

DTC Logic

INFOID:0000000009758654

DTC DETECTION LOGIC

NOTE:

• If DTC P1650 is displayed with DTC U1001, perform the trouble diagnosis for DTC U1001. Refer to 

EC-169,

"DTC Logic"

.

• If DTC P1650 is displayed with DTC P0607, perform the trouble diagnosis for DTC P0607. Refer to 

EC-350,

"Diagnosis Procedure"

.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting the next test.

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

3. Turn ignition switch OFF and wait at least 10 seconds.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A AND C

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

3. Turn ignition switch OFF and wait at least 10 seconds.

4. Check 1st trip DTC.
Is 1st trip DTC detected?

YES

>> Proceed to 

EC-400, "Diagnosis Procedure"

.

NO

>> GO TO 3.

DTC No.

CONSULT screen terms

(Trouble diagnosis con-

tent)

DTC detecting condition

Possible cause

P1650

STR MTR RELAY 2
(Starter motor relay 2)

A

Starter relay is stuck ON.

• Harness and connectors

(Between IPDM E/R harness connector and 
BCM harness connector is shorted to ground.)

• IPDM  E/R

B

Starter relay power supply circuit is 
excessively high voltage.

• Harness and connectors

(Between IPDM E/R harness connector and 
BCM harness is open or shorted to power.)
(Between IPDM E/R harness connector and bat-
tery is open.)

• IPDM  E/R

C

Starter relay circuit is excessively 
low voltage

• Harness and connectors

(Starter relay circuit is open or shorted.)

• IPDM  E/R