[Previous][Next]
DTC B1859: SW Fail
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
TROUBLE JUDGMENT
Check Conditions
  • Ignition switch: ON
Judgment Criterion
  • When the system detects an unfeasible voltage in the SOS switch/information switch indicator light system for 0.2 second or more.
  • When the SOS switch/information switch is ON for 3 minutes or more.
 
 
TROUBLESHOOTING HINTS
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
  • The ECALL&BCALL switch may be defective
  • The TCU may be defective
 
 
DIAGNOSIS
Required Special Tools
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
STEP 1. Using scan tool (M.U.T.-IIISE), check the data list.
Check the TCU data list (Refer to ).
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
 
Item No.Check conditionNormal condition
1
  • Ignition switch: ON
  • SOS switch/information switch: Non-operation
No switch press
Item No.Check conditionNormal condition
1
  • Ignition switch: ON
  • SOS switch/information switch: Non-operation
No switch press
Is the check result normal?
Go to Step 4.
Go to Step 2.
 
STEP 2. Check the SOS switch/information switch.
Check the resistance the SOS switch/information switch during operation/non-operation. Refer to .
Is the check result normal?
Go to Step 3.
Replace the ECALL&BCALL switch (Refer to ).
 
STEP 3. Resistance measurement at the ECALL&BCALL switch connector (terminals No. 11, 13).
(1) Disconnect the ECALL&BCALL switch connector, and measure at the wiring harness side.
(2) Check the resistance between the ECALL&BCALL switch connector (terminal No. 11) and body ground.
OK: No continuity
(3) Check the resistance between the ECALL&BCALL switch connector (terminal No. 13) and body ground.
OK: No continuity
Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness.
 
STEP 4. Check the SOS switch/information switch indicator light.
Check that the SOS switch/information switch indicator light illuminates. Refer to .
Is the check result normal?
Go to Step 5.
Replace the ECALL&BCALL switch (Refer to ).
 
STEP 5. Resistance measurement at between the TCU connector (ID1+, ID4+, ID5+, ID6+ terminals).
(1) Disconnect the TCU connector and ECALL&BCALL switch connector, and measure at the wiring harness side.
(2) Check the resistance between the TCU connector (ID1+, ID4+, ID5+, ID6+ terminals) and body ground.
OK: No continuity
(3) Check the continuity between the following terminals.
  • Check the resistance between the TCU connector (ID1+ terminal) and the ECALL&BCALL switch connector (except terminal No. 4).
  • Check the resistance between the TCU connector (ID4+ terminal) and the ECALL&BCALL switch connector (except terminal No. 5).
  • Check the resistance between the TCU connector (ID5+ terminal) and the ECALL&BCALL switch connector (except terminal No. 15).
  • Check the resistance between the TCU connector (ID6+ terminal) and the ECALL&BCALL switch connector (except terminal No. 16).
OK: No continuity
Is the check result normal?
Go to Step 6.
Repair the connector(s) or wiring harness.
 
STEP 6. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Check again if the DTC is set in the TCU.
(1) Erase the DTC.
(2) Turn the ignition switch from OFF position to ON position.
(3) Check the DTC.
Is the DTC set?
Replace the TCU (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).