Battery Monitoring Sensor
Blocking the brake energy regeneration function
The battery monitoring sensor can be diagnosed by the Engine control module (ECM). If the DTCs for the battery monitoring sensor are detected and the fault is active, the brake regeneration function is not permitted.
For vehicles with the automatic start/stop of the engine function, the function is not permitted temporarily.
Other situations where the battery monitoring sensor does not permit the brake regeneration function:
- The standby current consumption is more than 250 mA for 7 days. This means that the sensor never has the opportunity to measure the battery's standby current and therefore cannot calculate the battery's charge status.
On these occasions the sensor's calculation of the battery status is not reliable and the function is therefore not permitted.
Replacement of the battery / battery monitoring sensor
For replacing the battery or battery monitoring sensor, battery information must be reset.
The vehicle's battery is completely discharged or the battery monitoring sensor has been disconnected from the battery pole.
If the battery has been completely discharged so that the vehicle does not react to the ignition key (in principle, is completely dead) and the vehicle is then started using an external auxiliary battery or battery charger, the battery monitoring sensor can interpret this as it being disconnected from the battery (main battery). The battery monitoring sensor then reads off the battery voltage and assumes a SoC that is proportional to the voltage. If the SoC is low, the automatic start/stop of the engine function is not permitted.
For the battery monitoring sensor to calculate the battery's correct state of charge the vehicle must be in sleep mode for 4 hours . Sometimes, 6 hours in sleep mode may be required. This is on the condition that the ignition key has been removed, doors and hatches closed and the car is locked. If the SoC is still low, the automatic start/stop of the engine function will not be permitted. The battery then needs to be charged.