Nissan Xterra. Manual - part 320

EC-406

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

P1574 ASCD VEHICLE SPEED SENSOR

P1574 ASCD VEHICLE SPEED SENSOR

Component Description

INFOID:0000000009484145

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-28, "System Description"

 for ASCD functions.

On Board Diagnosis Logic

INFOID:0000000009484146

This self-diagnosis has the one trip detection logic.

The MIL will not illuminate for this diagnosis.

NOTE:

• If DTC P1574 is displayed with DTC UXXXX, first perform the trouble diagnosis for DTC UXXXX.

• If DTC P1574 is displayed with DTC P0607, first perform the trouble diagnosis for DTC P0607. Refer

to 

EC-365, "On Board Diagnosis Logic"

.

• If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500. Refer

to 

EC-350, "On Board Diagnosis Logic"

.

• If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer

to 

EC-363, "On Board Diagnosis Logic"

.

DTC Confirmation Procedure

INFOID:0000000009484147

CAUTION:

Always drive vehicle at a safe speed.

NOTE:

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-

ing the next step.

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.

TESTING CONDITION:

Step 3 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.
1. Start engine.
2. Drive the vehicle at more than 40 km/h (25 MPH).
3. Check DTC.
4. If DTC is detected, go to 

EC-406, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000009484148

1.

CHECK DTC WITH TCM

Check DTC with TCM. Refer to 

TM-101, "OBD-II Diagnostic Trouble Code (DTC)"

.

OK or NG

OK

>> GO TO 2.

NG

>> Perform trouble shooting relevant to DTC indicated.

2.

CHECK DTC WITH “ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)”

Refer to 

BRC-8, "Work Flow"

 (TYPE 1) or 

BRC-118, "Work Flow"

 (TYPE 2).

DTC No.

Trouble Diagnosis 

Name

DTC Detecting Condition

Possible Cause

P1574
1574

ASCD vehicle speed 
sensor

The difference between the two vehicle speed 
signals is out of the specified range.

• Harness or connectors

(The CAN communication line is open or 
shorted.)

• Combination meter
• ABS actuator and electric unit (control unit)
• Wheel sensor
• TCM
• ECM

P1574 ASCD VEHICLE SPEED SENSOR

EC-407

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace.

3.

CHECK COMBINATION METER FUNCTION

Refer to 

MWI-4, "Work Flow"

.

>> INSPECTION END

EC-408

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

P1715 INPUT SPEED SENSOR

P1715 INPUT SPEED SENSOR

Description

INFOID:0000000009484149

ECM receives input speed sensor signal from TCM through CAN communication line. ECM uses this signal for

engine control.

On Board Diagnosis Logic

INFOID:0000000009484150

NOTE:

• If DTC P1715 is displayed with DTC UXXXX first perform the trouble diagnosis for DTC UXXXX.

• If DTC P1715 is displayed with DTC P0607, first perform the trouble diagnosis for DTC P0607. Refer

to 

EC-365

.

• If DTC P1715 is displayed with DTC P0335, first perform the trouble diagnosis for DTC P0335. Refer

to 

EC-275

.

• If DTC P1715 is displayed with DTC P0340, P0345 first perform the trouble diagnosis for DTC P0340,

P0345. Refer to 

EC-278

.

• If DTC P1715 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer

to 

EC-363

.

The MIL will not illuminates for this diagnosis.

Diagnosis Procedure

INFOID:0000000009484151

1.

CHECK DTC WITH TCM

Check DTC with TCM. Refer to 

TM-101, "OBD-II Diagnostic Trouble Code (DTC)"

.

OK or NG

OK

>> GO TO 2.

NG

>> Perform trouble shooting relevant to DTC indicated.

2.

REPLACE TCM

Replace TCM. Refer to 

TM-234, "Removal and Installation"

.

>> INSPECTION END

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1715
1715

Input speed sensor
(TCM output)

Input speed sensor signal is different from 
the theoretical value calculated by ECM 
from output speed sensor signal and en-
gine rpm signal.

• Harness or connectors

(The CAN communication line is open or short-
ed)

• Harness or connectors

(Input speed sensor circuit is open or shorted)

• TCM

P1800 VIAS CONTROL SOLENOID VALVE 1

EC-409

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

P1800 VIAS CONTROL SOLENOID VALVE 1

Component Description

INFOID:0000000009484152

The VIAS control solenoid valve (2) cuts the intake manifold vacuum

signal for power valve control. It responds to ON/OFF signals from

the ECM. When the solenoid is off, the vacuum signal from the

intake manifold is cut. When the ECM sends an ON signal the coil

pulls the plunger downward and sends the vacuum signal to the

power valve actuator (1).

On Board Diagnosis Logic

INFOID:0000000009484153

The MIL will not illuminate for this self-diagnosis.

DTC Confirmation Procedure

INFOID:0000000009484154

NOTE:

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-

ing the next step.

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.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is between 11V at idle.
1. Start engine and let it idle for at least 5 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to 

EC-409, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000009484155

1.

CHECK VIAS CONTROL SOLENOID VALVE POWER SUPPLY CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect VIAS control solenoid valve harness connector.

3. Turn ignition switch ON.

4. Check voltage between terminal 1 and ground with CONSULT

or tester.

OK or NG

OK

>> GO TO 3.

NG

>> GO TO 2.

: Front

AWBIA0684ZZ

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1800
1800

VIAS control solenoid valve cir-
cuit 

An excessively low or high voltage signal 
is sent to ECM through the valve

• Harness or connectors

(The solenoid valve circuit is open or 
shorted.)

• VIAS control solenoid valve

1

: Power valve actuator

2

: VIAS control solenoid valve

: Front

Voltage: Battery voltage

AWBIA0684ZZ