1. The Key is turned - ignition input on the device becomes active
2. The device is then expecting a Driver ID input. If set to buzz on no DID, the reader will be buzzing at the user
3. The user scans their tag. If the tag is actually being read by the Driver ID module - you will hear 2 short beeps to indicate this.
4. If unsuccessful (the tag is not in the list on the device and the device is set to stay immobilized until there is a valid tag) the buzzing will continue to sound, and the vehicle will not start!

If successful, the buzzing will stop - the device proceeds with the next steps

1. Driver ID Tag Read log with Driver ID sent to the server (only successful scans are sent as a log with the tag data)
2. If the device is set to Immobilise if there is no DID, any digital outputs set to "Immobiliser" are turned off - you will see in Telemetry the digital output bit change from '1' to '0'
3. The output then toggles the relay it is wired to, allowing the vehicle to start as the starter motor circuit is completed.
4. The Vehicle is then able to Start

So the links in the chain are:

1. Keyfob -> Driver ID
2. Will the tag read?
3. Driver ID Reader (is it powered/connected?)
4. Is the harness intact and all connections solid? 
5. Driver List on Device. (This is covered by OEM parameters, TG set up for driver ID, and whether the list has actually been pushed to the device yet.)
6. Wiring and Relay set up. 

We will use these points as a reference to assist with debugging

My vehicle is immobilized and I cannot tag on

As with all debugging, this is a simple process of elimination checking all links in the chain. A few things can usually be gathered quite quickly. If the setup has been in operation for some time, and the same Tag/Device and setup is still in place, but the system stops working, we most likely have a hardware fault somewhere. For this reason, it is advisable to make use of parameter templates so that we can be sure the device is using a known working set of parameter templates.

• The other scenario is the tag has been removed from the driver list.
• No confirmation beep when the tag is scanned (i.e. tag won't scan)
• Checking the Tag and Reader hardware is OK. 
• Try another tag. If that one works, you have a dead tag. 
• Is the LED on the driver ID on? If not, it is not getting powered. For RFID readers, with the vehicle ignition on (this wakes up the unit and has it power on the reader) wiggle the wiring on the harness in these areas
• Wires on Molex plug connected to the driver ID reader
• Wires on the 4 way plug on the device harness
• 4 wires connected to the 4 way plug on the device side.
• In rare cases, the internal connection inside the RFID reader square box housing can come unplugged. Unscrew the housing and check all is seated.
• If the LED flickers, we have a bad connection. Replace the harness or RFID reader as necessary.
• For iButton readers the process is similar but there is less wiring and connections can be soldered so should be OK in most cases.

If the LED is on, and multiple tags won't scan (no beep) either the RFID module is faulty, or simply the buzzer (to sound the confirmation beep) is faulty. However, if the rest of the setup is fine, even if the buzzer is faulty the vehicle should still start/record the driver ID to Telematics Guru. So if you are experiencing problems.

• Parameters Set Up. 
• Check your parameters and wiring are correct for your application here:
• Driver ID Set-Up and Immobilisation
• Testing the Driver List is functioning
• If the confirmation beep sounds, but the vehicle does not immobilize, there is either an issue with the relay + wiring, device parameters or the driver list. 
• The driver list may not have yet been pushed to the device. This can quickly be determined by turning off the Test Against List option in parameters, ensuring they are pushed through (pending update column clears in OEM) and retrying. 
• If the tag was not in the list currently on the device - the tag will now work - as any tag scan will allow the vehicle to start.

You can check when the tag list on the device was last updated on the device by going to OEM and checking the Details page (link on the left of the device grid)

The time will be shown here (null in this case since no list has been sent to the device)

Telematics Guru pushes list changes to OEM every 30 minutes. After which point when the device connects in next it will get the list.

Still not working?

If a relay for immobilization is not installed - the troubleshooting process should be complete by now as you would have identified whether the tag, reader, or parameters are the issue. 

However, if a relay is installed, there are now 2 possible causes for the system not working

The output on the device is not working.

This is quite unlikely as the FETs that drive the outputs on devices are very robust and not likely to fail. But it is possible. You should see in telemetry that the digital output is toggling off on (at least according to what the device thinks) but if there is a hardware fault, this can be tested with a multimeter.
Put one lead on the output and the other on a voltage source. When the output toggles you will get the voltage level (as the output provides a ground) and then it will drop to 0 (as it is now high impedance)

Relay is faulty

12V relays typically work fine in 24V systems for a while, but then they burn out early. In this case, even though the correct inputs are being applied on the relay control, it won't toggle to allow the vehicle to be started. In this case, change the relay.