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LIN BUS LINE SYSTEM INSPECTION
 
 
cautionBefore replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
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. Measure the voltage at the LIN bus lines.
Check the LIN bus lines for short to power supply.
(1) Disconnect all the connectors leading to the LIN bus lines.
(2) Turn the power supply mode of the electric motor switch from OFF to ON.
(3) Measure the voltage between the column switch connector (DATA terminal) 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 the sunroof motor assembly connector (LIN2 terminal) and ground. <Vehicles with sunroof>
  • The voltmeter needle does not swing.
noteIf the LIN bus lines are short to power supply, the voltmeter indicates a constant value.
(5) Measure the voltage between the lighting control sensor connector (LIN2 terminal) and ground.
  • The voltmeter needle does not swing.
noteIf the LIN bus lines are short to power supply, the voltmeter indicates a constant value.
(6) Measure the voltage between the power window main switch connector (LIN terminal) and ground.
  • 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 2.
Repair the connector(s) or wiring harness.
 
STEP 2. Measure the resistance at the LIN bus lines.
Check the LIN bus lines for short to ground.
(1) Disconnect all the connectors leading to the LIN bus lines.
(2) Measure the resistance between the column switch connector (DATA terminal) and ground.
  • No continuity (1 kΩ or more)
(3) Measure the resistance between the sunroof motor assembly connector (LIN2 terminal) and ground. <Vehicles with sunroof>
  • No continuity (1 kΩ or more)
(4) Measure the resistance between the lighting control sensor connector (LIN2 terminal) and ground.
  • No continuity (1 kΩ or more)
(5) Measure the resistance between the power window main switch connector (LIN terminal) and ground.
  • No continuity (1 kΩ or more)
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Check the column switch.
Disconnect the column switch connector, and check whether the following DTC are set.
  • U0169 <Vehicles with sunroof>
  • U0215
  • U0231
(1) Connect all the relevant ECUs, and disconnect column switch connector only.
(2)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF 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) ."
(3) Erase the DTC.
(4) Turn the power supply mode of the electric motor switch from OFF to ON.
(5) Check whether DTC U0169*, U0215, and U0231 are set.
note*: Vehicles with sunroof
(6) Turn the power supply mode of the electric motor switch from OFF.
Is the DTC set?
Reconnect the column switch connector, and go to Step 4 <Vehicles with sunroof>.
Reconnect the column switch connector, and go to Step 5 <Vehicles without sunroof>.
Replace the column switch.
 
STEP 4. Check the sunroof motor assembly.
Disconnect the sunroof motor assembly connector, and check whether the following DTC are set.
  • U0215
  • U0231
  • U1109
(1) Connect all the relevant ECUs, and disconnect sunroof motor assembly connector only.
(2)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF 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) ."
(3) Erase the DTC.
(4) Turn the power supply mode of the electric motor switch from OFF to ON.
(5) Check whether DTC U0215, U0231 and U1109 are set.
(6) Turn the power supply mode of the electric motor switch from OFF.
Is the DTC set?
Reconnect the sunroof motor assembly connector, and go to Step 5.
Replace the sunroof motor assembly.
 
STEP 5. Check the lighting control sensor.
Disconnect lighting control sensor connector, and check whether the following DTC are set.
  • U0169 <Vehicles with sunroof>
  • U0215
  • U1109
(1) Connect all the relevant ECUs, and disconnect lighting control sensor connector only.
(2)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF 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) ."
(3) Erase the DTC.
(4) Turn the power supply mode of the electric motor switch from OFF to ON.
(5) Check whether DTC U0169*, U0215 and U1109 are set.
note*: Vehicles with sunroof
(6) Turn the power supply mode of the electric motor switch from OFF.
Is the DTC set?
Reconnect the lighting control sensor, and go to Step 6.
Replace the lighting control sensor (Refer to GROUP 54A - Lighting Control Sensor ).
 
STEP 6. Check the power window main switch.
Disconnect power window main switch connector, and check whether the following DTC are set.
  • U0169 <Vehicles with sunroof>
  • U0231
  • U1109
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF 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) Erase the DTC.
(3) Turn the power supply mode of the electric motor switch from OFF to ON.
(4) Check whether DTC U0169*, U0231 and U1109 are set.
note*: Vehicles with sunroof
(5) Turn the power supply mode of the electric motor switch from OFF.
Is the DTC set?
Reconnect the power window main switch, and go to Step 7.
Replace the power window main switch.
 
STEP 7. Recheck for DTC.
Check again if the DTC is set in the ETACS-ECU.
(1) Erase the DTC.
(2) Turn the power supply mode of the electric motor switch from OFF to ON.
(3) Check whether DTC U0169*, U0215, U0231 and U1109 are set.
note*: Vehicles with sunroof
(4) Turn the power supply mode of the electric motor switch from OFF.
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 ).