Have you had your car battery discharged?
The importance of having your car battery serviced especially if it is an older one, is very high. It will save you the headache of not being able to use the vehicle when it is most needed. But more importantly, there are components inside the car that will de-synchronise once the battery is flat, which can prevent the vehicle from either unlocking or starting.
The fact is, the lifespan of a car battery can be around 5-6 years. Its life span can be reduced or extended by the driving conditions and proper and regularly servicing the vehicle, including maintaining the battery.
In our experience, the following makes and models have had a common fault of de-synchronisation of the key with the car due to a flat battery. Here is the list:
1. Nissan Micra 2002-2010
The importance of having at all times a fully functional battery is critical for this particular model. When the battery is flat, and an attempt to start the car is made, the IMM and ECU modules are not communicating with each other. Therefore, the car would not start. This will prompt the P1611 NISSAN – Key ID discord IMM-ECU fault code. As possible causes for the P1611 are listed:
- Faulty or not programmed ignition key;
- Faulty IMM(immobiliser module) or ECU(engine control module).
To restore the vehicle to its full functionality, the ignition key, IMM and ECU modules have to be re-synchronised by using a dealer’s level equipment. The process can be lengthy, and it has to be done in a garage that is equipped and has experienced and trained technicians capable of handling the job correctly.
2. Honda Civic 2006-2011
When IMM and ECU modules stop communicating with each other due to a flat battery, the car is being prevented from starting. The only possible error or fault displayed would be the green key warning light flashing in the dashboard indicating an issue with the immobiliser. What this means, while the car battery is flat and an attempt is being made to start the car, the IMM and ECU module will de-synchronise. To restore the vehicle to its original settings, the two modules have to be synchronised again, so the ignition key, IMM and ECU module can communicate with each other and allow the car to start. This procedure can be done mobile, meaning an auto locksmith company can service the vehicle where it is parked, by using specialised equipment.
3. Vauxhall Corsa D 2006-2014
The Body Control Module also referred to as BCM is corrupted. This happens when an attempt to start the vehicle is made when the car battery is discharged. While there is not enough current stored into the battery to perform all the readings in between the modules when attempting to start the vehicle, the data in the BCM gets corrupted. To repair it, the BCM has to be reset and re-programmed to match all the security modules within the vehicle. When the BCM becomes corrupted possible codes that may appear after scanning are:
- P1632 – Wrong Transponder Key;
- P1678 – ECM (Engine Control Module) Identification Failed;
- P1679 – Wrong Environment Identifier Received BCM (Body Control Module);
- B3114 – Remote Key Not Synchronised;
- B3925 – Wrong Environment Identifier Received IPC (Instrument Cluster);
- B3929 – Wrong Environment Identifier Received SDM (Airbag).
4. BMW E-series
Had a flat battery and tried to start the car and couldn’t? If that happened, most likely now you have a 4A63 fault code which displays a warning of EWS tampering or EWS manipulation. What this means is that the DME and EWS modules have stopped communicating with each other when the attempt to start the vehicle was made while the battery was flat. To restore the vehicle to its functionality, the two modules have to be re-synchronised.
It has been reported that a de-synchronisation of the two modules may also occur, but not often after replacing the battery in which case, the re-synchronisation procedure needs to take place.
As a rule of thumb, for these particular makes and models especially, it is very important that the batteries are being serviced regularly or just as much as the oil is being replaced. Not doing so, in rare cases, it may cause some of the modules to get damaged while attempting to start the car when the battery is not fully charged. Any damaged modules will need to be replaced, which can bring the cost up versus maintaining or replacing the battery when due.