Code No. P1537: LIN Communication Error (Sending Message To Battery Current Sensor)

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 JUDGMENT

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.

Judgment Criterion

The data which is received from the engine-ECU remains abnormal for 2 seconds or more.

FAIL-SAFE AND BACKUP FUNCTION

None.

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, or check and repair harness between battery and battery current sensor connector terminal. Check power supply line for open/short circuit.

STEP 2. Check harness between battery and battery current sensor connector terminal.

Check power supply line for damage.

Q. Is the check result normal?

	Go to Step 3.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 3. Check harness between battery current sensor connector terminal and engine-ECU connector terminal LNBS.

Check signal line for open/short circuit and damage.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector, or repair the damaged harness wire.

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.