SOLUTIONS & TEST POINTS
The car's battery may be low or dead
Connect a better charger to see if you can get communication to any of the Control Modules
There is no power or voltage to the Control Units or the Scanner.
Ensure the Ignition Switch key is in the on position; otherwise, the entire system might not get the voltage it needs to communicate.
Broken, short-circuited, dirty or corroded Control Unit harness connectors causing bad contacts.
A factory scanner dedicated to the car brand is always recommended.
The scanner is not compatible or does not have the correct communication protocol to talk to the Control Units
A factory scanner dedicated to the car brand is On BMWs from 1995-2001 you have to scan through the Round 20 Pin connector under the hood, if there isn't one, connect through the regular OBD2 under the dash. It’s always recommended.
Are you using the correct diagnostic connector? (BMW Only)
On BMWs from 1995-2001, you have to scan through the Round 20 Pin connector under the hood, if there isn't one, connect through the regular OBD2 under the dash.
Are there other damaged electronic modules in the car?
If you have other electronic issues, such as a bad ABS, TCM, or Air Bag modules, it can break the communication line. Try disconnecting one module at a time, and re-test for scanner communication.
The car's Immobilizer "Drive-Block" is activated (Porsche 993 models)
Disable the "drive-block" system by pressing on the key fob button. This will enable communication to the DME (See our YouTube video).
Some of the testing procedures described in this guide could be dangerous if done improperly. We recommend that they are performed by an ASE certified mechanic
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