Code No.B1135 Engine switch


caution When replacing the ECU, always check that the communication circuit is normal.

DIAGNOSTIC FUNCTION



JUDGEMENT CRITERIA


Check Conditions
  • After OSS-ECU activation
Judgment Criterion
  • 3 seconds or more have elapsed since the unmatch between the SW1 and SW2 of engine switch is detected

PROBABLE CAUSES



  • Engine switch malfunction (ON/OFF seizure of SW1 or SW2)
  • Damaged wiring harness or connector (short to power supply, short to earth, or open circuit in SW1 or SW2 line)
  • Malfunction of OSS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Engine switch check
Refer to .

Q. Is the check result normal?
Go to Step 2.
Replace the engine switch.

STEP 2. M.U.T.-III data list
Check the OSS-ECU data list.

  • Operate the engine switch.
Operation state
 Item No.
 Check item
 Display
When the engine switch is pressed
 1
 Engine switch(1)
 ON
2
 Engine switch(2)
 ON
When the engine switch is not pressed
 1
 Engine switch(1)
 OFF
2
 Engine switch(2)
 OFF
OK: Operation state and data list display agree with each other.

Q. Is the check result normal?
Normal conditions are displayed for all the items. : Go to Step 5.
Normal condition is not displayed for item No.1 : Go to Step 3.
Normal condition is not displayed for item No. 2. : Go to Step 4.

STEP 3. Check of short to power supply, short to earth, and open circuit in SW1 line between OSS-ECU connector and engine switch connector

Q. Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.

STEP 4. Check of short to power supply, short to earth, and open circuit in SW2 line between OSS-ECU connector and engine switch connector
note Because the conformity cannot be determined even when the digital tester is used to measure the voltage of SW2 line between the OSS-ECU connector and engine switch connector, be sure to use the oscilloscope. (Outputs the sawtooth waveform of 0 to 5 V with intervals of 10 ms.)

Q. Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.

STEP 5. Check whether the diagnosis code is reset.

Q. Is the diagnosis code set?
Replace the OSS-ECU and register the chassis number (Refer to ).
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).