I think you mean you'll get the correct date your vehicle's service reminder was reset, not five years earlier. At least that's how it works on mine with "Service overdue 2009d" displayed today, January 3, 2026:
January 3, 2031 - 2009 = July 4, 2025.
I purchased the vehicle in October, 2025, so it is quite plausible the dealership took delivery of my vehicle and reset the service reminder in July, 2025.
What I'm saying is that on 1 January 2026, *exactly* 5 years worth of days was added to every Grenadier's next-service-required-date counter, including leap days. Or pretty damn close, but I think with or without leap days, we all got the same number of days added to our next service counters.
How it happened, why it happened, we'd need the code and hardware diagrams to figure out.
I'm going to call this next-service-due counter the Service counter. It starts at 0 (when the dealer resets it), and then counts up from 0, adding 1 to the counter each day at 1800 Eastern time / 0000 UTC+1 time. When the counter reaches 365, you start seeing Service Overdue by Xd messages on the console.
I picked up my Grenadier on 21 May 2025 (2025-05-21).
My Service counter on 2026-01-01 read 2051d.
When I subtract 5 years of days from 2026-01-01 (including leap days), plus the days since 2025-05-21, I get the date 2020-05-21.
My 2051 days is 5 years plus the distance in days since 21 May 2025.
Same MM and DD that I picked up my Grenadier, just wrong year.
I'm going to assume MileOne reset my Service counter on 21 May 2025.
I'm betting my Service counter read 140d or 141d on 31 December 2025, the number of days since 21 May 2025.
My Service counter thus should have reached 365d on 21 May 2026.
Essentially my Service counter is now saying my last Service counter reset was done on 21 May 2020. My Grenadier was assembled in March/April/May 2025.
I don't think the ECU is using the current date to calculate the next service due date. This is why it won't matter what dates you change in the console or anywhere else. And why disconnecting the battery and all other attempts to fix this won't work, unless they reset that Service counter to 0.
I think the ECU has a simple integer counter that at service reset is set to 0, and then increments by one day every day, and when it reaches one year + one day it begins reading service overdue on the console with the number of days past 365, continuing to increment one day every day. Or something like that.
Some people are reporting over 6000 days Service overdue -- well, at least one that I've seen on this site -- my guess is they haven't had their Service counter reset, or for some reason, a small number of ECUs had a different amount of days added to their Service counter.
If everyone has had their vehicle serviced by their due date, the maximum number of days Service overdue for anyone on 1 January 2026 would be 2192d if my math is correct. 2026-01-01 minus 2192d = 2020-01-01 (1 January 2020). Meaning your Service counter was actually reset to 0 on 2025-01-01.
I think the only way to fix is to do a service reset. Setting the console date manually will have no effect, and even if the ECU maintains its own date/time field, if the Service interval is managed by a counter that increments up from 0, it doesn't matter what you could set the ECU date/time or console date/time to, it won't affect or change the counter, as there is no decrementing the counter, only seems a reset to 0 is available.
/s.
