P1805

DTC P1805 BRAKE SWITCH

Description

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 Reference Value in Data Monitor Mode

Specification data are reference values.







On Board Diagnosis Logic

The MIL will not light up for this self-diagnosis.






FAIL-SAFE MODE

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







DTC Confirmation Procedure

1.Turn ignition switch ON.
2.Fully depress the brake pedal for at least 5 seconds.
3.Erase the DTC.
4.Check 1st trip DTC.
5.If 1st trip DTC is detected, go to .


Wiring Diagram






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 damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.







Diagnosis Procedure


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 (1) harness connector.





2.Check voltage between stop lamp switch terminal 1 and ground with CONSULT or tester.





Voltage: Battery voltage
OK or NG
OK- GO TO 4.
NG- GO TO 3.

3. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors M69, E7
- 10 A fuse
- 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 stop lamp switch harness connector.
2.Disconnect ECM harness connector.
3.Check harness continuity between stop lamp switch terminal 2 and ECM terminal 99.
Refer to Wiring Diagram.
Continuity should exist.
4.Also check harness for short to ground and short to power.
OK or NG
OK- GO TO 5.
NG- Repair open circuit or short to ground or short to power in harness connectors.

5. CHECK STOP LAMP SWITCH

.
OK or NG
OK- GO TO 6.
NG- Replace stop lamp switch. Removal And Installation.

6. CHECK INTERMITTENT INCIDENT

Refer to Trouble Diagnosis For Intermittent Incident
-INSPECTION END


Component Inspection


STOP LAMP SWITCH

1.Turn ignition switch OFF.
2.Disconnect stop lamp switch harness connector.
3.Check continuity between stop lamp switch terminals 1 and 2 under the following conditions.










If NG, adjust stop lamp switch installation, and perform step 3 again.