17. Can I test my FICM to ensure that it is the culprit?
If you aren't actually getting any codes, but would like to see if your FICM is the problem, you can easily test it. In fact, we encourage that all of our customers test their FICM's if it all possible just to be sure that it is indeed the cause of the issue they are experiencing!
If you have a ScanGauge II or Edge Insight CTS (of course available pre-programmed from us!), you can directly determine the voltage of your module through it. Other monitoring tools also allow this functionality, so it may make sense to look. If you have a ScanGauge that you didn't get from us and are curious on how to program it to grab FICM data, see the near end of this page.
If you don't have a monitoring tool, consider getting one as they are incredibly powerful little money savers that can alert you to issues before they leave you stranded, but for now read on...
To get the clearance necessary for testing manually, you will have to disconnect the two 3/8" coolant lines on the degas bottle, remove the two bolts holding it to the firewall, and pull the degas bottle off to the driver side of the vehicle. Be careful not to crack the bottom of the reservoir and feel free to drain some coolant and remove the reservoir entirely if that is a concern of yours. Also, please remember that when testing, engine cranking is necessary. As such, the water pump will be pumping coolant. Take care to not let coolant into the now-open FICM!
After the degas bottle is out, you'll see a small rectangular plate held on with two T20 torx screws on the top of the FICM. Remove these and you'll see four or seven screws, depending on your model.
For Four Screw Models - place your volt meter's positive lead on the screw closest to the driver's side of the vehicle - BE EXTREMELY CAREFUL NOT TO LET THIS LEAD SHORT OUT TO THE CASE. Place the meter's negative side lead on the negative terminal on one of the batteries. To prevent the lead from touching the case, many wrap all but the lead tips in electrical tape.
For Seven Screw Models - place your volt meter's positive lead on the screw closest to the PASSENGER side of the vehicle in the row with four screws - BE EXTREMELY CAREFUL NOT TO LET THIS LEAD SHORT OUT TO THE CASE. Place the meter's negative side lead on the negative terminal on one of the batteries. To prevent the lead from touching the case, many wrap all but the lead tips in electrical tape.
You are looking for anything above 45 volts (48 is ideal) with the key in the on position and for this voltage to not drop during cranking and running.
If your voltage is lower than 45 (the owner's Excursion was setting at less than 30 volts as an example), repair is needed. If you show zero volts out of the FICM, check your FICM fuse - it is a 50amp maxifuse typically located in the panel behind the driver's left knee in (typically) position 103.
If your voltage DOESN'T drop below 45 and you want a more difficult stress test on your module, look for less than 45 volts in the morning when the engine is completely cold. You are looking to test the voltage during the following events:
1. Key off (0 volts)
2. Key on during buzz test (48 volts)
3. Key on after buzz test (48 volts)
4. Cranking (48 volts)
5. Running IMMEDIATELY after cold start and for the first minute (48 volts)
6. RPM's at 2000 after it's been started for a minute (48 volts)
Again, if the voltage drops below 45, even for a second, during any of these tests, the FICM needs repair.
Of course, it's materially easier to review these voltages with a monitor like the ScanGauge II or, even better, the Edge Insight CTS. We have both of these tools available on our Intake Form.