Code No. P0515: Battery Temperature Sensor System <Vehicles with AS&G system>

OPERATION

A power voltage of 5 V is applied to the battery temperature sensor output terminal (terminal No. 2) of the battery current sensor connector from the engine-ECU (terminal No. 131).
The power voltage is earthed to the engine-ECU (terminal No. 112) from the battery temperature sensor (terminal No. 3).

FUNCTION

The battery temperature sensor converts the battery temperature into a voltage and inputs the voltage signal to the engine-ECU.
In response to the signal, the engine-ECU controls the discharge and charge control.
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

2 seconds later after the ignition switch has been in "ON" position or the engine has started up.

Judgment Criterion

The sensor output voltage is 4.6 V or more (battery temperature of below -50°C or equivalent) for 2 seconds.

The sensor output voltage is 0.2 V or less (battery temperature of above 100°C or equivalent) for 2 seconds.

PROBABLE CAUSES

Failed battery temperature sensor
Open or shorted battery temperature sensor circuit, harness damage, or connector damage
Failed engine-ECU

DIAGNOSIS PROCEDURE

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

Item No. 160: Battery temperature sensor

OK: At ambient temperature (atmospheric temperature) 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. Connector check: A-39 battery current sensor connector

Q. Is the check result normal?

Go to Step 3 .

Repair or replace the connector.

STEP 3. Check battery temperature sensor itself.

Check battery temperature sensor itself (Refer to GROUP 54A - Battery - Inspection - Battery Current Sensor Check <Vehicles with AS&G system> ).

Q. Is the check result normal?

	Go to Step 4 .

	Replace the battery current sensor.

STEP 4. Perform resistance measurement at A-39 battery current sensor connector.

Disconnect connector, and measure at harness side.
Resistance between terminal No. 3 and earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 8 .

Go to Step 5 .

STEP 5. Connector check: A-09 engine-ECU connector

Q. Is the check result normal?

Go to Step 6 .

Repair or replace the connector.

STEP 6. Check harness between A-39 (terminal No. 3) battery current sensor connector and A-09 (terminal No. 112) engine-ECU connector.

Check earthing line for open circuit and damage.

Q. Is the check result normal?

Go to Step 7 .

Repair the damaged harness wire.

STEP 7. M.U.T.-III data list

Item No. 160: Battery temperature sensor

OK: At ambient temperature (atmospheric temperature) 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 then perform the variant coding (Refer to GROUP 00 - Precautions Before Service - How to Perform Variant Coding ).

STEP 8. Perform voltage measurement at A-39 battery current sensor connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 2 and earth.

OK: 4.5 - 4.9 V

Q. Is the check result normal?

Go to Step 11 .

Go to Step 9 .

STEP 9. Connector check: A-09 engine-ECU connector

Q. Is the check result normal?

Go to Step 10 .

Repair or replace the connector.

STEP 10. Check harness between A-39 (terminal No. 2) battery current sensor connector and A-09 (terminal No. 131) engine-ECU connector.

Check output line for open/short circuit.

Q. Is the check result normal?

Go to Step 7 .

Repair the damaged harness wire.

STEP 11. Connector check: A-09 engine-ECU connector

Q. Is the check result normal?

Go to Step 12 .

Repair or replace the connector.

STEP 12. Check harness between A-39 (terminal No. 2) battery current sensor connector and A-09 (terminal No. 131) engine-ECU connector.

Check output line for damage.

Q. Is the check result normal?

Go to Step 7 .

Repair the damaged harness wire.