The Mitsubishi Outlander PHEV is a nice and very reliable EV, but it has one issue: battery degradation is not measured but estimated, assuming loss of battery capacity based on the calendar, but also based on charging cycles. Typically, this estimate is too pessimistic and therefore, the Battery Management Unit (BMU) does not allow to use fully the real battery capacity.

However, using a so called Drive Battery Capacity Automatic Measurement (DBCAM), the BMU will drain the battery to 0% (by switching on air condition and heating simultaneously which is a good way to consume significantly energy without actually driving) and after that, the battery gets fully charged and while charging, the BMU measures how many energy is charged. This measured value replaces then the estimated battery capacity, giving you a some range back.

The following describes using the Thinkcar Thinkscan 689 diagnostic tablet to do this. This diagnostic tablet has the advantage that it can be used without an expensive subscription. While the diagnostic tablet needs to be bought once, it pays of in comparison to paying your car dealer every year to the DBCAM.

Also the app PHEV Watchdog lite is used (together with an OBD Bluetooth adapter) to read and store BMU data.

Cell smoothing

It might that doing a cell smoothing before the DBCAM gives even better DBCAM results! But whether this is worth it depends on the min/max voltage of the cells: only if the delta is 0.050V or more, its worth it. For assessing the cell drift, use PHEV Watchdog lite and it is best to do this with an empty battery.

However, for a cell smoothing, the batteries need to be full! (Just like a normal cell balance at the end of charging. But the difference is that cell balancing charges the cells that are not yet full, using the tiny resistors for those cells that are already full, i.e. I charges cells so that they reach the voltage of the fuller cells. Whereas the smoothing uses the tiny resistors to discharge those cells that have a higher voltage than the other cells.) So, first do fully charge before you start a cell smoothing.

Connect: Plug your Thinkcar diagnostic tablet into the OBD port while the vehicle is fully OFF.

Ignition to READY: Turn the vehicle on to READY mode (foot on the brake, press power). Note: This is different from the DBCAM, which requires the car to just be in the "ON" accessory mode.

Navigate: Open the Thinkcar app, decode your VIN, and navigate to System Selection -> BMU.

Execute: Select Special Function -> Cell voltage smoothing.

Confirm: Press the button to execute the command.

Monitor: The Thinkcar screen will show an "Execution status." You simply wait until that status changes from "Active" to "Not Active" to confirm the balancing is completely finished.

Time: The process can take up to a maximum of 2 hours to complete.

Tablet Power: Your Thinkcar tablet must not go to sleep or turn off its screen during this process. If it does, the connection will drop, and the procedure will abort and throw an error. Plug your tablet into a charger and set its display settings to stay awake indefinitely.

DBCAM

You may find on the web a Mitsubishi Service Bulletin MSB-17EXL54-501 (filename: MSB-17EXL54-501.pdf) that describes the procedure using the Mitsubishi M.U.T.-III diagnostic tablet. The following is based on that description:

If you like, connect PHEV Watchdog lite in order to make there a new reading of the current battery condition (connect via Bluetooth, then via three dots: Battery Condition -- when connected via Bluetooth, it should immediately record a new reading. By tapping on it, you can delete a reading in case you made too many recordings of the same state).

1. Drive the drive battery to empty
2. Have car switched off
3. Connect charging cable: car will start charging (even though we want to have the battery empty, but as it is anyway a slow charger, it is no problem that this will now actually start charging the car)
4. Connect the diagnostic tablet (I had the car switched on, but I had later, in step 17., to switch my car off for the DBCAM to start: try next time to leave it switched off! The Mitsubishi Service Bulletin MSB-17EXL54-501 also mentions that the car should be switched off before connecting their diagnostic tablet.)
5. Do the VIN scan: click the large VIN button
6. Click: Automatically Search. It will then show Vehicle information, click: OK
7. Click: System Selection
8. Scroll down to and click: BMU
9. Scroll down to and click: Special Function
10. Scroll down to and click: Battery Auto Capacity Measured, confirm with: Yes
11. As DBCAM is currently not running, but maybe completed some earlier run, Execution Status should be either: Not run (if you never did a DBCAM) or Complete (from the previous DBCAM)
12. Scroll down: Auto Capa.Measured Result HIS.1 to 10 should show the history of previous DBCAMs battery capacity measurements (or the original capacity, 40 in case of my MY 2017), Auto Capa.Measured Result HIS. 1 to 10 should show the odometer readings from previous DBCAMS, or 0).
13. Note down what value is shown for Battery Current Capacity -- after DBCAM completed, it should have changed (and will hopefully be a higher number as it is using the measured instead of the too pessimistically value calculated by the BMU).
14. At the very bottom of the list, Capa. Measured Discharge Current should show NG/Not Performed
15. At the bottom right, click: Perform (to start the DBCAM) and confirm with: yes. It should then say: Successful Operation, press: OK
16. Execution Status should now be: Executing
17. As I had my car still switched on, at the very bottom of the list, Capa. Measured Discharge Current was still showing: NG/Not Performed
18. Finally, after switching off my car, the fan, AC, heater, turned on (i.e. everything that consumes energy in order to empty the drive battery to 0%). The diagnostic tablet was still running and did then display in the list at the very bottom, Capa. Measured Discharge Current was still showing: Ok
19. As the car was in my garage, I did not lock it, but it should be possible to lock the car now.

As the fan and heater are running to drain the battery, this means: Success. Emptying the drive battery to 0% will now take some hours (aprox. 1-2 h). All documentation says that is is now possible to disconnect the diagnostic table (and connect later again to check).

I did let the diagnostic table connected, but after some time, the car put anyway the OBD port to sleep, so the diagnostic tablet did disconnect. I left my car in my garage, i.e. I did not lock the car doors.

Sooner or later, the battery is empty and fan, AC, etc. should go off. The car should now have automatically started a new charging session, i.e. charge the empty battery (and while doing that, it will measure how much it is able to charge the battery to determine the real capacity): the red charging symbol in the dashboard should be on.

While it was charging, I did re-connect my diagnostic tablet to the car:

1. I did the above VIN scan, but when selecting: Automatically Search, it did return an error and I had to manually enter the VIN (even though it did just display the VIN a few seconds before).
2. After that, I was able to select: System selection
3. BMU
4. Special Function
5. Battery Auto Capacity Measured
6. Execution Status should still show: Executing
7. Capa. Measured Discharge Current should show again: NG/Not Performed

When this measured charging session finished (will take longer than a normal charge that would start at ca. 30%, as this time the charge starts at 0%), the red charge light in the dashboard should go off.

I then connected the diagnostic table again and switched on the car.
I still had the charging cable connected and interestingly the 12 V battery light was on, i.e. the OBC was not charging the 12 V battery, but the car was in accessory mode (I am pretty sure that I had pressed the brake pedal while switching the car on). I then switched the car off, disconnected the charging cable and then, switched the car on: the 12 V light was gone.

1. I did the usual VIN scan, and Automatically Search did work again this time.
2. After that, I was able to select: System selection
3. BMU
4. Special Function
5. Battery Auto Capacity Measured
6. Execution Status should be: Complete,
7. Error status should still be: No error
8. Capa. Measured Discharge Current should show again: NG/Not Performed
9. Battery Current Capacity should show a new value (hopefully higher than the old value).
10. Also the HIS 1 value should have been shifted to HIS.2 and so on.

The DBCAM is now finished and you can disconnect the diagnostic tablet. If you like, connect PHEV Watchdog lite. It should say that a new capacity measurement is available and via Battery Condition, the DBCAM should be shown and the new (hopefully better) capacity should be shown.

TPMS Valves programming

Thinkcar also has a device for reading TPMS valves, transfer that via Blueetoth to the diagnostics tablet and then writing the valve ID via the diagnostics tablet to the Outlander. That TPMS reader might only work with Thinkcar valves, though?