Code No. P0515: Battery Temperature Sensor System

OPERATION

A power voltage of 5 V is applied to the battery temperature sensor output terminal from the engine-ECU connector terminal BTS.
The power voltage is earthed to the engine-ECU connector terminal AFSE&ECBE from the battery temperature sensor connector terminal.

FUNCTION

The battery temperature sensor converts the battery temperature into a voltage and inputs the signal to the engine-ECU.
In response to the signal, the engine-ECU controls charging and discharging.
The battery temperature sensor is a kind of resistor, which has characteristics to reduce its resistance as the battery temperature rises. Therefore, the sensor output voltage varies with the battery temperature, and becomes lower as the battery temperature rises.

TROUBLE JUDGMENT

Check Condition

Battery positive voltage is 8 - 16 V.
2 seconds later after the ignition switch has been in "ON" position or the engine has started up.

Judgment Criterion

The battery temperature sensor output voltage is more than 4.88 V.

The battery temperature sensor output voltage is less than 0.09 V.

FAIL-SAFE AND BACKUP FUNCTION

The AS&G control is prohibited.

PROBABLE CAUSES

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

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Item No. 402: Battery temperature sensor

OK: At ambient temperature (atmospheric temperature) of battery temperature sensor, or equivalent

Q. Is the check result normal?

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

	Go to Step 2.

STEP 2. Check battery temperature sensor itself.

Battery current sensor connector check.
Check battery temperature sensor itself (Refer to GROUP 54A - Battery - On-vehicle Service - Battery Current Sensor Check <2200> ).

Q. Is the check result normal?

	Go to Step 3.

	Repair or replace the connector, or replace the battery current sensor.

STEP 3. Perform voltage measurement at battery current sensor connector.

Disconnect connector and measure at harness side.
Ignition switch: ON
Voltage between terminal engine-ECU BTS line and body earth.

OK: 4.5 - 4.9 V

Q. Is the check result normal?

	Go to Step 6.

	Go to Step 4.

STEP 4. Check harness between battery current sensor connector terminal and engine-ECU connector terminal BTS.

Check output line for open/short circuit.

Q. Is the check result normal?

	Go to Step 5.

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

STEP 5. M.U.T.-III data list

Item No. 402: Battery temperature sensor

OK: At ambient temperature (atmospheric temperature) of battery temperature sensor, or equivalent

Q. Is the check result normal?

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

	Replace the engine-ECU.

STEP 6. Perform resistance measurement at battery current sensor connector.

Disconnect connector and measure at harness side.
Resistance between terminal engine-ECU AFSE&ECBE line and body earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 8.

	Go to Step 7.

STEP 7. Check harness between battery current sensor connector terminal and engine-ECU connector terminal AFSE&ECBE.

Check earthing line for open circuit and damage.

Q. Is the check result normal?

	Go to Step 5.

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

STEP 8. Check harness between battery current sensor connector terminal and engine-ECU connector terminal BTS.

Check output line for damage.

Q. Is the check result normal?

	Go to Step 5.

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