The battery temperature sensor is incorporated into the battery current sensor and it informs the engine-ECU of battery temperature via the Local Interconnect Network (LIN).
In response to the signal, the engine-ECU controls charging and discharging.
TROUBLE JUDGEMENT
Check Condition
After 2 seconds since the ignition switch is turned ON or since the completion of engine start.
Battery positive voltage is more than 10 V and is less than 16.5 V.
Judgement Criterion
For 2 seconds, the battery temperature information from battery temperature sensor is abnormal.
FAIL-SAFE AND BACKUP FUNCTION
Prohibits alternator output suppression control against current consumers. (operates as a normal alternator.)
PROBABLE CAUSES
Failed battery temperature sensor
Failed engine-ECU
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III diagnosis code
Reconfirmation of diagnosis code.
Q.
Is diagnosis code set?
Go to Step 2.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
STEP 2. Replace the battery current sensor
After replacing the battery current sensor, reconfirm whether the diagnosis code is set.