Infiniti Q45. Manual - part 495

DTC P1800 VIAS CONTROL SOLENOID VALVE

EC-619

C

D

E

F

G

H

I

J

K

L

M

A

EC

Specification data are reference values and are measured between each terminal and ground.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

Diagnostic Procedure

NBS0025N

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 VIAS control solenoid valve terminal 1
and ground with CONSULT-II or tester.

OK or NG

OK

>> GO TO 3.

NG

>> GO TO 2.

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

29

PU

VIAS control solenoid valve

[Engine is running]

●

Selector lever: P or N

0 - 1.0V

[Engine is running]

●

Selector lever: D

●

Engine speed: Below 5,000 rpm

BATTERY VOLTAGE
(11 - 14V)

[Engine is running]

●

Engine speed: Above 5,000 rpm

0 - 1.0V

111

W/B

ECM relay
(Self shut-off)

[Engine is running]
[Ignition switch: OFF]

●

For a few seconds after turning ignition 
switch OFF

0 - 1.5V

[Ignition switch: OFF]

●

More than a few seconds after turning igni-
tion switch OFF

BATTERY VOLTAGE
(11 - 14V)

119

120

R
R

Power supply for ECM

[Ignition switch: ON]

BATTERY VOLTAGE
(11 - 14V)

PBIB2421E

Voltage: Battery voltage

PBIB0173E

EC-620

DTC P1800 VIAS CONTROL SOLENOID VALVE

2. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors M135, F105

●

Harness for open or short between VIAS control solenoid valve and ECM relay

>> Repair harness or connectors.

3. 

CHECK VIAS CONTROL SOLENOID VALVE OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check harness continuity between ECM terminal 29 and VIAS control solenoid valve terminal 2.
Refer to Wiring Diagram.

4.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 4.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

4. 

CHECK VIAS CONTROL SOLENOID VALVE

Refer to 

EC-620, "Component Inspection"

 .

OK or NG

OK

>> GO TO 5.

NG

>> Replace VIAS control solenoid valve.

5. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-145, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

NBS0025O

VIAS CONTROL SOLENOID VALVE

 With CONSULT-II

1.

Reconnect harness connectors disconnected.

2.

Turn ignition switch ON.

3.

Perform “VIAS SOL VALVE” in “ACTIVE TEST” mode.

4.

Check air passage continuity and operation delay time under the
following conditions.

Operation takes less than 1 second.

Continuity should exist.

Condition

VIAS SOL VALVE

Air passage continuity 

between A and B

Air passage continuity 

between A and C

ON

Yes

No

OFF

No

Yes

PBIB0177E

DTC P1800 VIAS CONTROL SOLENOID VALVE

EC-621

C

D

E

F

G

H

I

J

K

L

M

A

EC

 Without CONSULT-II

Check air passage continuity and operation delay time under the fol-
lowing conditions.

Operation takes less than 1 second.

Removal and Installation

NBS0025P

VIAS CONTROL SOLENOID VALVE

Refer to 

EM-19, "INTAKE MANIFOLD"

 .

Condition

Air passage continuity 

between A and B

Air passage continuity 

between A and C

12V direct current supply 
between terminals 1 and 2

Yes

No

No supply

No

Yes

MEC488B

EC-622

DTC P1805 BRAKE SWITCH

DTC P1805 BRAKE SWITCH

PFP:25320

Description

NBS0025Q

Brake switch signal is applied to the ECM through the stop lamp switch when the brake pedal is depressed.
This signal is used mainly to decrease the engine speed when the vehicle is driving.

CONSULT-II Reference Value in Data Monitor Mode

NBS0025R

Specification data are reference values.

On Board Diagnosis Logic

NBS0025S

The MIL will not light up for this diagnosis.

FAIL-SAFE MODE

When the malfunction is detected, the ECM enters fail-safe mode.

DTC Confirmation Procedure

NBS0025T

 WITH CONSULT-II

1.

Turn ignition switch ON.

2.

Fully depress the brake pedal for at least 5 seconds.

3.

Erase the DTC with CONSULT-II.

4.

Select “DATA MONITOR” mode with CONSULT-II.

5.

If 1st trip DTC is detected, go to 

EC-624, "Diagnostic Procedure"

.

 WITH GST

Follow the procedure WITH CONSULT-II above.

MONITOR ITEM

CONDITION

SPECIFICATION

BRAKE SW

●

Ignition switch: ON

Brake pedal: Fully released

OFF

Brake pedal: Slightly depressed

ON

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1805
1805

Brake switch

A brake switch signal is not sent to ECM for 
extremely long time while the vehicle is driving.

●

Harness or connectors
(Stop lamp switch circuit is open or 
shorted.)

●

Stop lamp switch

Engine operation condition in fail-fail safe mode

ECM controls the electric throttle control actuator by regulating the throttle opening to a small range.Therefore, acceleration will be 
poor.

Vehicle condition

Driving condition

When engine is idling

Normal

When accelerating

Poor acceleration

PBIB1952E