Code No.U1570 No-Bus activity error (LIN)














TROUBLE JUDGEMENT



PROBABLE CAUSES



  • Malfunction of the ETACS-ECU
  • Malfunction of the slave ECU
  • LIN bus lines shorted to power supply
  • LIN bus lines shorted to earth

DIAGNOSIS PROCEDURE

STEP 1. Check the following connectors.
Check the following connectors:

  • B-317 ETACS-ECU connectors
  • B-201 Column switch connector

Q. Are all the connectors in good condition?
Go to Step 2.
Repair the defective connector.

STEP 2. Check the following wiring harness.
Check the wiring harness for open circuit between the following connectors:

  • Wiring harness from B-317 ETACS-ECU connector terminal No.54 to B-212 column switch connector terminal No.3.
note Prior to the wiring harness inspection, check joint connectors B-03 <RHD>, and repair if necessary.

Q. Are all the wiring harness wires in good condition?
Go to Step 3.
Repair the wiring harness.

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 connecter to the LIN bus lines.
(2)Turn the erectric motor switch from "LOCK" (OFF) to "ON" position.
(3)Measure the voltage between B-201 column switch connector terminal No.3 and earth.

  • The voltmeter needle does not swing.
note If the LIN bus lines are short to power supply, the voltmeter indicates a constant value.

Q. Is the check result normal?
Go to Step 4.
Repair the wiring harness.

STEP 4. Measure the resistance at the LIN bus lines.
Check the LIN bus lines for short to earth.
(1)Disconnect all the connectors which are connecter to the LIN bus lines.
(2)Measure the resistance value between B-201 column switch connector terminal No.3 and earth.

  • No continuity (1 kΩ or more)

Q. Is the check result normal?
Go to Step 5.
Repair the wiring harness.

STEP 5. Check the column switch.
Disconnect B-201 column switch connector, and recheck whether diagnosis code No. U1570 is set.
(1)Connect all the relevant ECUs, and disconnect B-201 column switch connector only.
(2)Erase the diagnosis code.
(3)Turn the erectric motor switch from "LOCK" (OFF) to "ON" position.
(4)Check whether diagnosis code No. U1570 is set.
note If diagnosis code No. U1570 is not set, diagnosis code No. U1500 is set because the column switch is disconnected. This is normal.
(5)Turn the erectric motor switch to the "LOCK" (OFF) position.

Q. Is diagnosis code No. U1570 set?
Reconnect the column switch connector, and go to Step 6.
Replace the lighting switch.

STEP 6. Recheck for diagnosis code.
Check again if the diagnosis code is set to the ETACS-ECU.
(1)Erase the diagnosis code.
(2)Turn the erectric motor switch from "LOCK" (OFF) to "ON" position.
(3)Check whether diagnosis code No. U1570 is set.
(4)Turn the erectric motor switch to the "LOCK" (OFF) position.

Q. Is the diagnosis code set?
Replace the ETACS-ECU and register the ID codes (Refer to GROUP 54A, Immobilizer system - On-vehicles service ).
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).