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LIN BUS LINE SYSTEM INSPECTION
 
 
 
 
 
 
COMMENTS ON TROUBLE SYMPTOM
If the slave ECU does not work normally, the LIN bus line, the slave ECU or the ETACS-ECU may be defective.
 
 
PROBABLE CAUSES
  • The ETACS-ECU may be defective.
  • The slave ECU may be defective.
  • LIN bus lines shorted to power supply
  • LIN bus lines shorted to ground
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the following connectors.
Check the following connectors:
  • ETACS-ECU connectors C-411 and C-416
  • Column switch connector C-314
  • Lighting control sensor connector E-08 <Vehicles with auto light function>
Are all the connectors in good condition?
Go to Step 2.
Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection .
 
STEP 2. Check the following wiring harness.
Check the wiring harness for open circuit between the following connectors:
  • Wiring harness from ETACS-ECU connector C-411 (terminal 1) to column switch connector C-314 (terminal 3)
  • Wiring harness from ETACS-ECU connector C-416 (terminal 1) to lighting control sensor connector E-08 (terminal 2) <Vehicles with auto light function>
Are all the wiring harness wires in good condition?
Go to Step 3.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 3. Measure the voltage at the LIN bus lines.
Check the LIN bus lines for short to power supply.
(1) Disconnect all the connectors which are connector to the LIN bus lines.
(2) Turn the ignition switch from "LOCK" (OFF) to "ON" position.
(3) Measure the voltage between column switch connector C-314 (terminal 3) and ground.
  • The voltmeter needle does not swing.
noteIf the LIN bus lines are short to power supply, the voltmeter indicates a constant value.
(4) Measure the voltage between lighting control sensor connector E-08 (terminal 2) and ground. <Vehicles with auto light function>
  • The voltmeter needle does not swing.
noteIf the LIN bus lines are short to power supply, the voltmeter indicates a constant value.
Is the check result normal?
Go to Step 4.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 4. Measure the resistance at the LIN bus lines.
Check the LIN bus lines for short to ground.
(1) Disconnect all the connectors which are connected to the LIN bus lines.
(2) Measure the resistance value between column switch connector C-314 (terminal 3) and ground.
  • No continuity (1 kΩ or more)
(3) Measure the resistance value between lighting control sensor connector E-08 (terminal 2) and ground. <Vehicles with auto light function>
  • No continuity (1 kΩ or more)
Is the check result normal?
Go to Step 5.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 5. Check the column switch.
Disconnect the C-314 column switch assembly connector, and check whether the following DTC U0231* is set.
note*: Vehicles with auto light function
(1)
cautionTo prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(2) Connect all the relevant ECUs, and disconnect column switch connector C-314 only.
(3) Erase the DTC.
(4) Turn the ignition switch from "LOCK" (OFF) to "ON" position.
(5) Check whether DTC U0231* is set.
note*: Vehicles with auto light function
(6) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC set?
Reconnect the column switch connector, and go to Step 6 <Vehicles with auto light function>.
Reconnect the column switch connector, and go to Step 7 <Vehicles without auto light function>.
Replace the column switch assembly.
 
STEP 6. Check the lighting control sensor.
Disconnect lighting control sensor connector E-08, and check whether the following DTC U1109 is set.
(1) Connect all the relevant ECUs, and disconnect lighting control sensor connector E-08 only.
(2) Erase the DTC.
(3) Turn the ignition switch from "LOCK" (OFF) to "ON" position.
(4) Check whether DTC U1109 is set.
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC set?
Reconnect the lighting control sensor connector, and go to Step 7.
Replace the lighting control sensor.
 
STEP 7. Recheck for diagnostic trouble code.
Check again if the DTC is set in the ETACS-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) to "ON" position.
(3) Check whether DTC U0231* and U1109 are set.
note*: Vehicles with auto light function
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC set?
Replace the ETACS-ECU.
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).