Infiniti Q45. Manual - part 496

DTC P1805 BRAKE SWITCH

EC-623

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Wiring Diagram

NBS0025U

TBWM1249E

EC-624

DTC P1805 BRAKE SWITCH

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

NBS0025V

1. 

CHECK STOP LAMP SWITCH CIRCUIT

1.

Turn ignition switch OFF.

2.

Check the stop lamp when depressing and releasing the brake pedal.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 2.

2. 

CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT 

1.

Disconnect stop lamp switch harness connector.

2.

Check voltage between stop lamp switch terminal 3 and ground
with CONSULT-II or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

TER-

MINAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

101

R/W

Stop lamp switch

[Ignition switch: OFF]

●

Brake pedal: Fully released

Approximately 0V

[Ignition switch: OFF]

●

Brake pedal: Slightly depressed

BATTERY VOLTAGE
(11 - 14V)

Brake pedal

Stop lamp

Fully released

Not illuminated

Slightly depressed

Illuminated

PBIB2433E

Voltage: Battery voltage

PBIB2102E

DTC P1805 BRAKE SWITCH

EC-625

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3. 

DETECT MALFUNCTIONING PART

Check the following.

●

Fuse block (J/B) No. 1 connector M1

●

10A fuse

●

Harness connectors M61, M401

●

Harness for open and short between stop lamp switch and battery

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

4. 

CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Disconnect ECM harness connector.

2.

Disconnect stop lamp switch harness connector.

3.

Check harness continuity between ECM terminal 101 and stop
lamp switch terminal 4.
Refer to Wiring Diagram.

4.

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

OK or NG

OK

>> GO TO 6.

NG

>> GO TO 5.

5. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors M401, M61

●

Harness connectors M135, F105

●

Harness for open or short between ECM and stop lamp switch

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

6. 

CHECK STOP LAMP SWITCH 

Refer to 

EC-626, "Component Inspection"

 .

OK or NG

OK

>> GO TO 7.

NG

>> Replace stop lamp switch.

7. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-145, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Continuity should exist.

PBIB2433E

EC-626

DTC P1805 BRAKE SWITCH

Component Inspection

NBS0025W

STOP LAMP SWITCH

1.

Turn ignition switch OFF.

2.

Disconnect stop lamp switch harness connector.

3.

Check continuity between stop lamp switch terminals 3 and 4
under the following conditions.

4.

If NG, adjust stop lamp switch installation, refer to 

BR-6,

"BRAKE PEDAL"

 , and perform step 3 again.

Conditions

Continuity

Brake pedal: Fully released

Should not exist.

Brake pedal: Slightly depressed

Should exist.

PBIB2103E