Code No.U1515 No bus activity error for LIN

caution

Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
When the ETACS-ECU of vehicles without KOS is replaced, the encrypted code of the ignition key needs to be registered to the ETACS-ECU. (If the encrypted code is not registered, the engine cannot be started. Register the encrypted code as described in GROUP 54A, Immobilizer System - How to Register Key ID .)

TROUBLE JUDGMENT

The ETACS-ECU will store diagnosis code No. U1515 when no communication has been carried out for more than a certain period after it received last valid data.

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. 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 ignition switch from "LOCK" (OFF) to "ON" position.

(3)Measure the voltage between the column switch connector (power supply terminal) and the body earth.

The voltmeter needle does not swing.

note

If 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 (power supply terminal) and the body earth. <vehicles with sunroof>

The voltmeter needle does not swing.

note

If 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 (power supply terminal) and the body earth. <vehicles with lighting control sensor>

The voltmeter needle does not swing.

note

If the LIN bus lines are short to power supply, the voltmeter indicates a constant value.

(6)Measure the voltage between the security alarm sensor connector (power supply terminal) and the body earth. <vehicles with security alarm sensor>

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 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 earth.

(1)Disconnect all the connectors which are connecter to the LIN bus lines.

(2)Measure the resistance between the column switch connector (earth terminal) and the body earth.

No continuity (1 kΩ or more)

(3)Measure the resistance between the sunroof motor assembly connector (earth terminal) and the body earth. <vehicles with sunroof>

No continuity (1 kΩ or more)

(4)Measure the resistance between the lighting control sensor connector (earth terminal) and the body earth. <vehicles with lighting control sensor>

No continuity (1 kΩ or more)

(5)Measure the resistance between the security alarm sensor connector (earth terminal) and the body earth. <vehicles with security alarm sensor>

No continuity (1 kΩ or more)

Q. Is the check result normal?

	Go to Step 3.

	Repair the connector(s) or wiring harness.

STEP 3. Check the column switch.

Disconnect column switch connector, and recheck whether diagnosis code No. U1515 is set.

(1)Connect all the relevant ECUs, and disconnect column switch connector only.

(2)Erase the diagnosis code.

(3)Turn the ignition switch from "LOCK" (OFF) to "ON" position.

(4)Check whether diagnosis code No. U1515 is set.

note

If diagnosis code No. U1515 is not set, diagnosis code No. U1109 is set because the column switch is disconnected. This is normal.

(5)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is diagnosis code No. U1515 set?

	Reconnect the column switch connector, and go to Step 4.

	Replace the wiper/washer switch.

STEP 4. Check the sunroof motor assembly.

Disconnect sunroof motor assembly connector, and recheck whether diagnosis code No. U1515 is set.

(1)Connect all the relevant ECUs, and disconnect sunroof motor assembly connector only.

(2)Erase the diagnosis code.

(3)Turn the ignition switch from "LOCK" (OFF) to "ON" position.

(4)Check whether diagnosis code No. U1515 is set.

note

If diagnosis code No. U1515 is not set, diagnosis code No. U0169 is set because the sunroof motor assembly is disconnected. This is normal.

(5)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is diagnosis code No. U1515 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 recheck whether diagnosis code No. U1515 is set.

(1)Connect all the relevant ECUs, and disconnect lighting control sensor connector only.

(2)Erase the diagnosis code.

(3)Turn the ignition switch from "LOCK" (OFF) to "ON" position.

(4)Check whether diagnosis code No. U1515 is set.

note

If diagnosis code No. U1515 is not set, diagnosis code No. U0231 is set because the lighting control sensor is disconnected. This is normal.

(5)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is diagnosis code No. U1515 set?

	Reconnect the lighting control sensor, and go to Step 6.

	Replace the lighting control sensor.

STEP 6. Check the security alarm sensor.

Disconnect security alarm sensor connector, and recheck whether diagnosis code No. U1515 is set.

(1)Connect all the relevant ECUs, and disconnect security alarm sensor connector only.

(2)Erase the diagnosis code.

(3)Turn the ignition switch from "LOCK" (OFF) to "ON" position.

(4)Check whether diagnosis code No. U1515 is set.

note

If diagnosis code No. U1515 is not set, diagnosis code No. U1007 is set because the security alarm sensor is disconnected. This is normal.

(5)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is diagnosis code No. U1515 set?

	Reconnect the security alarm sensor connector, and go to Step 7.

	Replace the security alarm sensor.

STEP 7. Recheck for diagnosis code.

Check again if the diagnosis code is set to the ETACS-ECU.

(1)Erase the diagnosis code.

(2)Turn the ignition switch from "LOCK" (OFF) to "ON" position.

(3)Check whether diagnosis code No. U1515 is set.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the diagnosis code set?

	Replace the ETACS-ECU.

	The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).