Code No. P1538: LIN Communication Error (Receiving Message From Battery Current Sensor) <Vehicles for Thailand>

OPERATION

Power is supplied by the battery to the Battery current sensor connector terminal.
The battery current sensor sends a signal to the engine-ECU connector terminal LNBS via the Local Interconnect Network (LIN).

FUNCTION

The engine-ECU monitors the status of the Local Interconnect Network (LIN) between the engine-ECU and the battery current sensor.

TROUBLE JUDGEMENT

Check Condition

2 seconds later after the ignition switch has been in ON position or just after the engine has started up.
Battery positive voltage is more than 10 V and is less than 16.5 V.

Judgement Criterion

The engine-ECU cannot receive the data from the Battery sensor.

FAIL-SAFE AND BACKUP FUNCTION

Prohibits alternator output suppression control against current consumers. (operates as a normal alternator.)

PROBABLE CAUSES

Failed battery current sensor.
Open/short circuit or harness damage in battery current sensor circuit or loose connector contact.
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Perform voltage measurement at battery current sensor connector.

Disconnect connector, and measure at harness side.
Ignition switch: "ON"
Voltage between terminal power supply line and body earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 2.

	Repair or replace the connector(s), or check and repair the harness of open circuit and short to earth in power supply line between battery and battery current sensor connector.

STEP 2. Check of damage in power supply line between battery and battery current sensor connector terminal.

Q. Is the check result normal?

	Go to Step 3.

	Repair the connector(s) or wiring harness.

STEP 3. Check of open circuit, short to earth, and damage in LNBS line between battery current sensor connector terminal and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 4.

	Repair the connector(s) or wiring harness.

STEP 4. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is diagnosis code set?

	Go to Step 5.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 5. Replace the battery current sensor

After replacing the battery current sensor, reconfirm whether the diagnosis code is set.

Q. Is the diagnosis code set?

	Replace the engine-ECU.

	Check end.