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DTC B1856: Speaker Connection
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
TROUBLE JUDGMENT
Check Conditions
  • Ignition switch: From OFF to ON
Judgment Criterion
  • If the system detects that the ECALL speaker is disconnected for 5 seconds 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 speaker may be defective
  • The ECALL relay box assembly 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 special function.
(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) ."
(2) Check the ECALL speaker (Refer to ).
Test
  • Item No.2: Emergency speaker check (Beep)
OK: A beep sound is heard (during the test).
Is the check result normal?
Go to Step 6.
Go to Step 2.
 
STEP 2. Resistance measurement at the TCU connector (SPO+ terminal).
(1) Disconnect the TCU connector, and measure at the wiring harness side.
(2) Check the resistance between the TCU connector terminal SPO+ and SPO-.
OK: 1.5 - 70 ohms
(3) Check the resistance between the TCU connector (SPO+ terminal) and body ground.
OK: No continuity
Is the check result normal?
Go to Step 6.
Go to Step 3.
 
STEP 3. Resistance measurement at the TCU connector (SPO+, SPO- terminals).
(1) Disconnect the TCU connector and the ECALL relay box assembly connector, and measure at the wiring harness side.
(2) Check the resistance between the TCU connector (SPO+ terminal) and the ECALL relay box assembly connector (ESI+ terminal).
OK: The resistance should be 2 ohms or less
(3) Check the resistance between the TCU connector (SPO- terminal) and the ECALL relay box assembly connector (ESI- terminal).
OK: The resistance should be 2 ohms or less
(4) Check the resistance between the TCU connector (SPO+ terminal) and body ground.
OK: No continuity
(5) Check the resistance between the TCU connector (SPO- terminal) and body ground.
OK: No continuity
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Resistance measurement at the ECALL relay box assembly connector (ESO-, ESO+ terminals).
(1) Disconnect the ECALL relay box assembly connector, and measure at the wiring harness side.
(2) Check the resistance between the ECALL relay box assembly connector (ESO- terminal) and (ESO+ terminal).
OK: 1.5 - 70 ohms
(3) Check the resistance between the ECALL relay box assembly connector (ESO+ terminal) and body ground.
OK: No continuity
Is the check result normal?
Replace the ECALL relay box assembly (Refer to ).
Go to Step 5.
 
STEP 5. Resistance measurement at the ECALL relay box assembly connector (ESO-, ESO+ terminals).
(1) Disconnect the ECALL relay box assembly and the ECALL speaker connector, and measure at the wiring harness side.
(2) Check the resistance between the ECALL relay box assembly connector (ESO+ terminal) and the ECALL speaker connector (terminal No. 2).
OK: The resistance should be 2 ohms or less
(3) Check the resistance between the ECALL relay box assembly connector (ESO- terminal) and the ECALL speaker connector (terminal No. 1).
OK: The resistance should be 2 ohms or less
(4) Check the resistance between the ECALL relay box assembly connector (ESO+ terminal) and body ground.
OK: No continuity
(5) Check the resistance between the ECALL relay box assembly connector (ESO- terminal) and body ground.
OK: No continuity
Is the check result normal?
Replace the ECALL speaker (Refer to ).
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 "LOCK" (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 ).