Forgetting the stops

Disconnecting or installing a new battery is a common enough repair found in all service centers across the country; all technicians have preformed this service multiple times. The technician determined the battery was faulty (for whatever reason) and it was replaced. Or, possibly the cables were disconnected due to some repair procedure. However, this simple task, if not given enough attention, can sometimes shift a customer’s perception of a service center after the work has been completed.
All technicians are aware that they should reset the clock and re-enter the preset radio stations (if they recorded them) after a battery disconnect. Most technicians also have experienced the radio security feature lock up on them after a battery disconnect. This situation is usually drawn to their attention and can usually be addressed quite quickly by entering in a pre-programmed code to return the radio back to operation.
What some shops are now experiencing is a customer returning days later with any variety of concerns not immediately identified to be related to the disconnecting of the battery on the previous repair. Conditions they may be experiencing can include: the air conditioning system is stuck in one position, drivability and performance concerns or windows and doors not operating as expected. The systems most likely to be affected (depending on model) are electronically controlled transmissions, heating and air conditioning actuators, power sliding doors, power lift gates and power windows.
What these systems are loosing is their learned operating range or “soft stops.” These specifications are used to allow the control module to determine when a system is operating outside of conditions it has determined to be “normal.” This may be a physical position or a learned voltage or amperage reading. Each of these systems’ features has its own reset procedure, some requiring the use of the scan tool. Others require the system to be operated in a specific manner to relearn its stops. Many of these systems may reset on their own as the owner drives the vehicle eventually reaching all the prerequisites needed to record a setting into its memory.
Often air conditioning electronic actuators, when they have experienced battery power loss, will need to relearn their “normal” operating range. When the operating position is lost, the system may default — usually to full heat and to the defrost mode of operation.
If the battery is left disconnected long enough, the transmission adapts can also be lost from memory creating unfamiliar shift patterns for the customer until new operating parameters are programmed into the controller’s memory.
Some power sliding doors, if not relearned, will stay in learn mode and not let their door control modules power down when the ignition is cycled off. This creates a parasitic draw on the new battery, quite often depleting its energy overnight. This scenario never sits well with a customer who just paid to have a battery replaced.
One of the more common concerns now seen after a battery disconnect, is the auto (or express) up feature of the power windows becomes inoperative. Quite often when this feature is disabled, the anti-pinch or auto-reverse feature may also not function. Resetting the function of these features often requires the operation of the window in a specific timed sequence. This can be a rather precise procedure on some vehicles, where holding a switch for four seconds means four seconds not three or five. It’s not uncommon to have to repeat the steps more than once to get them to re-initialize. A stop watch may be useful for accomplishing this procedure. Once completed, always confirm the operation of both the auto up and auto reverse features. Keep in mind that this feature is also often found on sunroofs as well.
A little research before disconnecting a battery cable can go along way to keeping your customer happy and returning.
For more information on automotive technology visit CARS OnDemand training at: www.carsondemand.com