Whether you are reprogramming onboard or off board, you must be sure that the power supplied to the module does not drop below 11.5 - 12 volts. Some reprogramming operations with the key-on will turn on cooling fans, fuel pumps, and other components that will cause the battery to drain faster than normal. Instead of pulling fuses to prevent the battery drain, it is easier and more practical to have the vehicle connected to a charger or jump pack. During reprogramming there is a risk of having the operation fail if voltage falls below the proper operating voltage. Sometimes a failed operation can be recovered, but there is a chance that failed reprogramming could ruin the control module. To mitigate this risk, put a high quality battery charger on the vehicle if you are reprogramming onboard or use a good bench top power supply if you are reprogramming offboard.
Updated Calibrations One important step in the service process is determining of a vehicle needs a calibration update. The J2534 subscription software will usually tell you if an update is needed, but sometimes only after you pay the subscription fee. That makes it tough to check for updates without encountering some type of fee. If you want to find out before you purchase the subscription, you can usually find a table, PDF, or matrix on the manufacturer’s website telling you if there are updated calibrations. For example, Chrysler has a flash matrix available at http://techauthority.com under the J2534 Flash availability section. For GM vehicles, you can visit http://calid.gm.com and type in the VIN or part number to learn if updates are available. Figure 5 shows GM’s CalID site. At www.motorcraftservice.com, there is a link in the reprogramming section called Latest Calibration Information. That link will open an Excel sheet that lists all of the PCM tag codes, and shows what updates are available. You should note that a calibration update may be available even if there is not a specific TSB calling for it.
Using J2534-1 Because each automaker has different software, you should become comfortable with one automaker’s service before you start on the next. Start by reprogramming a vehicle you have regular access to before accepting vehicles from walk-in customers. Take your time and follow the steps at the automaker’s website. If you have questions, call the automaker’s customer support number or your PassThru tool vendor. J2534 reprogramming requires a PC and Internet, and the technician reflashing cars should be computer savvy. If you are uncomfortable using a PC and the Internet, you may want to seek out an independent trainer in your area and attend a J2534 class.
When you provide reprogramming service to a customer there are several things you should consider. First, reprogramming is a service that cannot be reversed. If you update the calibration in the customer’s car, there is no method to put the old calibration back in. There is a chance the new calibration will change noticeable characteristics in the way the customer’s car drives. It may raise or lower the idle, change the shifts or idle speed control, or other settings meant to solve a warranty issue, economy issue, or emissions issue. There is no way to revert back if the customer doesn’t like one of the new settings.
Drew Technologies, Copyright 2009