P1805

DTC P1805 BRAKE SWITCH





Component Description





Brake switch signal is applied to the ECM through the stop lamp switch (1) when the brake pedal is depressed. This signal is used mainly to decrease the engine speed when the vehicle is being driven.
- ICC brake switch (models with ICC) (2)
- ASCD brake switch (models with ASCD) (2)




CONSULT-III Reference Value in Data Monitor Mode
Specification data are reference values.









On Board Diagnosis Logic
The MIL will not illuminate for this diagnosis.






FAIL-SAFE MODE
When the malfunction is detected, ECM enters 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 P1805.




Wiring Diagram





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

CAUTION:
Never 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

ICC MODELS
1.CHECK DTC WITH ICC SENSOR INTEGRATED UNIT
Self-Diagnostic Function.
OK or NG
OK - GO TO 2.
NG - Repair or replace malfunctioning part.
2.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 5.
NG - GO TO 3.
3.CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT





1. Disconnect stop lamp switch (1) harness connector.
- ICC brake switch (2)





2. Disconnect ICC brake hold relay (1) harness connector.
- : Vehicle front





3. Check voltage between stop lamp switch terminal 1 and ground with CONSULT-III or tester.

Voltage: Battery voltage






4. Check voltage between ICC brake hold relay terminal 3 and ground with CONSULT-III or tester.

Continuity should exist.

OK or NG
OK - GO TO 5.
NG - GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
- Fuse block (J/B) connector E101
- 10 A fuse
- Harness for open or short between battery and stop lamp switch
- Harness for open or short between battery and ICC brake hold relay
- Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between the following;
ECM terminal 101 and stop lamp switch terminal 2, ECM terminal 101 and ICC brake hold relay terminal 5. Refer to Wiring Diagram.

Continuity should exist.

3. Also check harness for short to ground and short to power.
OK or NG
OK - GO TO 7.
NG - GO TO 6.
6.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E108, M15
- Harness for open or short between ECM and stop lamp switch
- Harness for open or short between ECM and ICC brake hold relay
- Repair open circuit or short to ground or short to power in harness or connectors.
7.CHECK STOP LAMP SWITCH
P1805.
OK or NG
OK - GO TO 8.
NG - Replace stop lamp switch.
8.CHECK ICC BRAKE HOLD RELAY
P1805.
OK - GO TO 9.
NG - Replace ICC brake hold relay.
9.CHECK INTERMITTENT INCIDENT
Diagnosis Procedure.
- INSPECTION END

ASCD MODELS
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.
- ASCD brake switch (2)





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

Voltage: Battery voltage

OK or NG
OK - GO TO 4.
NG - GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
- Fuse block (J/B) connector E101
- 10 A fuse
- 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 SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 101 and stop lamp switch terminal 2. Refer to Wiring Diagram.

Continuity should exist.

3. 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 E108, M15
- 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
P1805.
OK or NG
OK - GO TO 7.
NG - Replace stop lamp switch.
7.CHECK INTERMITTENT INCIDENT
Diagnosis Procedure.
- 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.





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

ICC BRAKE HOLD RELAY





1. Check continuity between ICC brake hold relay terminals 3 and
5 under the following conditions.





2. If NG, replace ICC brake hold relay.