# Handling 8-bit Fuel Counter Rollover via RealDash CAN (Renault vehicle)

**URL:** <https://forum.realdash.net/t/handling-8-bit-fuel-counter-rollover-via-realdash-can-renault-vehicle/10154>\
**Category:** Connectivity\
**Created:** [April 1, 2026, 12:45pm UTC](https://forum.realdash.net/t/handling-8-bit-fuel-counter-rollover-via-realdash-can-renault-vehicle/10154 "2026-04-01T12:45:55Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![ppbayeta](https://forum.realdash.net/letter_avatar_proxy/v4/letter/p/f1d935/32.png) [@ppbayeta](https://forum.realdash.net/u/ppbayeta)\
**Post date:** [April 1, 2026, 12:45pm UTC](https://forum.realdash.net/t/handling-8-bit-fuel-counter-rollover-via-realdash-can-renault-vehicle/10154/1 "2026-04-01T12:45:55Z")

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**Hi RealDash Team,**

​I am using an ESP32 as a CAN-to-USB bridge to display data from a Renault vehicle in RealDash using the RealDash CAN protocol.

​The vehicle provides an 8-bit rolling counter (0-255) for fuel consumption. Each increment represents exactly **80mm³** of fuel. Because it is only 8 bits, the value rolls over from 255 back to 0 very frequently (every 20.48 ml of fuel consumed).

​ **My questions regarding the best implementation are:**

1. ​If I map this 8-bit value to **TargetID 258 (Fuel Consumed)**, does RealDash internally detect the rollover (255 → 0) and continue to accumulate the total volume? Or will the “Total Fuel Consumed” value reset or glitch when the byte wraps around?
2. ​Given that I have a fixed increment of 80mm³ per pulse, would you recommend:

- ​**A)** Sending the raw 8-bit counter and letting RealDash handle it (if rollover detection exists).
- ​**B)** Linearizing the value in the ESP32 (sending a continuous 32-bit float/int representing total Liters) and mapping that to **ID 258**.
- ​**C)** Using **TargetID 490 (Fuel Flow)**? (Though my data is a volume counter, not a flow rate).

1. ​For long-term stats (average consumption, trip fuel), does RealDash persistence for **ID 258** work better if the “Total Consumed” value is an ever-increasing number provided by the hardware?

​ **Setup Details:**

- ​ **Connection:** USB (Serial) @ 921600bps.
- ​ **Protocol:** RealDash CAN.

​Thank you for your time and for such a great tool!

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**Author:** ![realdashdev](https://forum.realdash.net/user_avatar/forum.realdash.net/realdashdev/32/6_2.png) [@realdashdev](https://forum.realdash.net/u/realdashdev)\
**Post date:** [April 7, 2026, 9:57am UTC](https://forum.realdash.net/t/handling-8-bit-fuel-counter-rollover-via-realdash-can-renault-vehicle/10154/2 "2026-04-07T09:57:12Z")

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1. No, the rollover is not detected and Total Fuel Consumed would just reset when value rolls over 255.
2. Option B is the best for total fuel consumed, Option C is what we use to give instant Fuel Flow to RealDash to handle all the rest of the calculations.
3. I believe best option is to send instant fuel flow to RealDash and let RD handle the rest.

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**Author:** ![azizov.agalar](https://forum.realdash.net/letter_avatar_proxy/v4/letter/a/46a35a/32.png) [@azizov.agalar](https://forum.realdash.net/u/azizov.agalar)\
**Post date:** [June 28, 2026, 10:00am UTC](https://forum.realdash.net/t/handling-8-bit-fuel-counter-rollover-via-realdash-can-renault-vehicle/10154/3 "2026-06-28T10:00:50Z")

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Good afternoon.  
I’m setting up RealDash for a Renault Megane 2 Phase 2.  
Have you achieved the correct fuel consumption calculation?

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**Author:** ![realdashdev](https://forum.realdash.net/user_avatar/forum.realdash.net/realdashdev/32/6_2.png) [@realdashdev](https://forum.realdash.net/u/realdashdev)\
**Post date:** [August 3, 2026, 6:53am UTC](https://forum.realdash.net/t/handling-8-bit-fuel-counter-rollover-via-realdash-can-renault-vehicle/10154/4 "2026-08-03T06:53:26Z")

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Currently, no development has been done on the rollover values. We do have this on the radar though.