Engine Controls

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 being driven.


DTC Logic


DTC DETECTION LOGIC







DTC CONFIRMATION PROCEDURE


1. PERFORM DTC CONFIRMATION PROCEDURE

1.Turn ignition switch ON.
2.Fully depress the brake pedal for at least 5 seconds.
3.Erase the DTC with CONSULT.
4.Check 1st trip DTC.
Is 1st trip DTC detected?
YES- Go to Diagnosis Procedure (see below).
NO- INSPECTION END


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.





Is the inspection result normal?
YES- GO TO 4.
NO- GO TO 2.

2. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT

1.Turn ignition switch OFF.
2.Disconnect stop lamp switch harness connector.
3.Check the voltage between stop lamp switch harness connector and ground.





Is the inspection result normal?
YES- GO TO 4.
NO- GO TO 3.

3. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors E105, M77
- 10A fuse (No. 11)
- Harness for open or 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 RELAY GROUND CIRCUIT

1.Turn ignition switch OFF.
2.Disconnect stop lamp relay harness connector.
3.Check the continuity between stop lamp relay harness connector and and ground.





Is the inspection result normal?
YES- GO TO 5.
NO- Repair open circuit or short to ground or short to power in harness or connectors.

5. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT

1.Connect stop lamp switch harness connector.
2.Turn ignition switch ON.
3.Check the voltage between stop lamp relay harness connector and ground.





Is the inspection result normal?
YES- GO TO 7.
NO- GO TO 6.

6. DETECT MALFUNCTIONING PART

Check the harness for open or short between stop lamp switch and stop lamp relay.
Is the inspection result normal?
YES- GO TO 9.
NO- Repair open circuit or short to ground or short to power in harness or connectors.

7. CHECK STOP LAMP RELAY POWER SUPPLY CIRCUIT

Check the voltage between stop lamp relay harness connector and ground.





Is the inspection result normal?
YES- GO TO 8.
NO- Repair open circuit or short to ground or short to power in harness or connectors.

8. CHECK STOP LAMP RELAY INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.Turn ignition switch OFF.
2.Disconnect stop lamp relay harness connector.
3.Check the continuity between stop lamp relay harness connector and ECM harness connector.





4.Also check harness for short to ground and short to power.
Is the inspection result normal?
YES- GO TO 10.
NO- Repair open circuit or short to ground or short to power in harness or connectors.

9. CHECK STOP LAMP SWITCH

.
Is the inspection result normal?
YES- GO TO 11.
NO- Replace stop lamp switch. Removal And Installation.

10. CHECK STOP LAMP RELAY

.
Is the inspection result normal?
YES- GO TO 11.
NO- Replace stop lamp relay.

11. CHECK INTERMITTENT INCIDENT

Intermittent Incident.
- INSPECTION END


Component Inspection (Stop Lamp Switch)


1. CHECK STOP LAMP SWITCH-I

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





Is the inspection result normal?
YES- INSPECTION END
NO- GO TO 2.

2. CHECK STOP LAMP SWITCH-II

1.Adjust stop lamp switch installation. Adjustments.
2.Check the continuity between stop lamp switch terminals under the following conditions.





Is the inspection result normal?
YES- INSPECTION END
NO- Replace stop lamp switch. Removal And Installation.


Component Inspection (Stop Lamp Relay)


1. STOP LAMP RELAY

1.Turn ignition switch OFF.
2.Remove stop lamp relay.





3.Check continuity between stop lamp relay terminals under the following conditions.





Is the inspection result normal?
YES- INSPECTION END
NO- Replace stop lamp relay.