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DTC U1515: No-Bus activity error (LIN)
 
 
 
 
 
 
TROUBLE JUDGMENT
The ETACS-ECU will store DTC U1515 when no communication has been carried out for more than a certain period after it received last valid data.
 
 
TROUBLESHOOTING HINTS
  • 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 3) <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 ECU connectors which are connected 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 3) 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 ECU 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 3) 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 column switch connector C-314, and recheck whether DTC U1515 is stored.
(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 U1515 is stored.
noteIf DTC U1515 is not stored, DTC U1109 is stored because the column switch is disconnected. This is normal.
(6) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC U1515 stored?
Reconnect the column switch connector, and go to Step 6.
Replace the column switch assembly.
 
STEP 6. Check the lighting control sensor.
Disconnect lighting control sensor connector E-08, and recheck whether DTC U1515 is stored.
(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 U1515 is stored.
noteIf DTC U1515 is not stored, DTC U0231 is stored because the power lighting control sensor is disconnected. This is normal.
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC U1515 stored?
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 stored in the ETACS-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) to "ON" position.
(3) Check whether DTC U1515 is stored.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC stored?
Replace the ETACS-ECU.
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).