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How to Read 850 Mileage with an ELM327: 1996 & 1997 850

MVS Forums Contributor esl_97_850_T5  explains in clear instructions how to read 850 mileage with an ELM 327 unit: “Contrary to conventional wisdom here and on other Volvo sites, the mileage of the 1996 and 1997 Volvo 850 cars can be read from the COMBI (Instrument Panel computer) using an ELM327 device. It does not require a Volvo Scan Tool (VST) or other high cost scanner.”

If you have an ELM327 v1.4 or higher, and if you can already use the ELM327 to communicate with the Volvo 850 to obtain the emission diagnostics DTCs via the ELM327 commands:


How to read 1996-1997 Volvo 850 mileage with an ELM327

>ATTA 13
>ATWM 82 51 13 A1
>ATSH 84 51 13

If you cut and paste those commands and the ELM327’s responses — most especially the B90300 and B90400 commands and their responses — into the “Paste Volvo 850 communication here” box at:

It will attempt to interpret the communication and display (what is thought to be) the “Vehicle Mileage” and the “Mileage at Service Light Reset”.

It could be that I’ve misinterpreted the meaning of those 2 mileages and that they need to be added together to come up with the “Vehicle Mileage”. You’ll just have to try it and see.

Keep in mind that these two mileages do not include any “lost miles” that were impossible to record because the ABS module was not supplying a proper speed signal to the COMBI. It could be that some of the other B9nn data can be used to estimate those “lost miles”.

[Note: I use the term ECU to generally refer to “electronic control unit”, ie, all the car’s computers or computer-like modules, rather than the more common usage as “engine control unit” to refer strictly to the engine’s computer.]

For lots more information on how to retrieve all the COMBI’s (ie, ECU 51’s) B9nn data, suggestions how it might be interpreted, and ideas on how to guess the “lost miles”, refer to: … leage.html

or check out all the pages and .rtf files that feed from my “Volvo 850 OBDII” portal:

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