Polo 9N: Protocol Specification & Details

Hi there,

"Since my Polo 9N doesn't have a multi-function display, but I would still like to see things like fuel consumption, I'm looking for the protocol specification. Does anyone happen to have this information, or can you tell me where I might be able to find it?"

Thank you very much and best regards.
Ozzy.

You can find a PDF document with detailed instructions on how to obtain RPM and fuel consumption data in VAG vehicles within this forum.
If you need something more - write what exactly, and maybe someone can help .

Hi,

I was searching for the information you requested in this forum, but I couldn't find anything. Could you please provide me with a link to the PDF you mentioned?

Ozzy wrote:

Hi, I was looking for the requested information in this forum, but I didn't find anything. Could you please provide me with a link to the mentioned PDF?

Here it is.
https://www.canhack.de/en/viewtopic.php?t=1979

"I tested this on a VW Passat B6, so I think it should work on your Polo as well."

I just installed an onboard computer in our Polo.
If anyone would like information about it, just let me know .
Displayed is...
- the outside temperature
- Current fuel consumption from 15 km/h, expressed in liters per 100 kilometers.
otherwise, l/h (with "H" displayed).
- kilometers since last reset.
- Liters since last reset.
- Average consumption since last reset.

Built with an Arduino Nano, a CAN bus adapter, and two 7-segment displays.
To store the distance traveled and fuel consumption, an RTC (Real-Time Clock) is needed.

Hello, how did you calculate the temperature?

Hi,

The temperature is located at address 0x420 in the instrument cluster, within byte 2 (starting at position 0).
I obtained 4 values from VCDS and determined the corresponding value within each byte by blowing hot air into it with a hairdryer.
I then entered the values into a graph and extended the straight line through the origin.

Outdoor temperature = (Byte_0x420_2 - 101) / 2;

When the light is turned on, the display dims, and this setting is located in byte 5 of address 0x420.

text
Byte_0x420_5 = rxBuf[5]; // Turn on the light.
Light = Byte_0x420_5 & 0x50;

When the light sensor reading is greater than 0, the display is set to its minimum brightness.

Here are some more details about the required CAN IDs.

Code:

if (rxId==0x288) //0x288 Tempomat ein       {       Byte_0x288_2=rxBuf[2];       TempomatEin=Byte_0x288_2 & B01000000;  //Status Tempomat aktiv       } if (rxId==0x320)       {       Byte_0x320_2=rxBuf[2];       Tankinhalt=Byte_0x320_2;  //Tankinhalt in Liter       } if (rxId==0x420) //0x420 Außentemperatur vom KI  421 vom Tester       {       Byte_0x420_2=rxBuf[2];  //Außentemperatur       Byte_0x420_3=rxBuf[3];  //Öltemperatur       Byte_0x420_5=rxBuf[5];  //Licht ein       Licht=Byte_0x420_5 & B01010000;       ATmp=10*(Byte_0x420_2-100)/2;       oelt=Byte_0x420_3-60;       } if (rxId==0x5A0) //0x5A0 Geschwindigkeit vom ABS       {       Byte_0x5A0_1=rxBuf[1]; //Geschwindigkeit LB       Byte_0x5A0_2=rxBuf[2]; //Geschwindigkeit HB       Byte_0x5A0_5=rxBuf[5]; //Wegstrecke LB       Byte_0x5A0_6=rxBuf[6]; //Wegstrecke HB       Kmh=(Byte_0x5A0_2*254+Byte_0x5A0_1)/152;       CurrentStrecke=Byte_0x5A0_5 + (Byte_0x5A0_6 & B00000111)*256;       } if (rxId==0x480) //0x480 Verbrauch vom MSG, Berechnung in ml       {       Byte_0x480_1=rxBuf[1];  //MIL&EPC       Byte_0x480_2=rxBuf[2];  //Verbrauch_LB       Byte_0x480_3=rxBuf[3];  //Verbrauch_HB       MIL=Byte_0x480_1 & B00001000;       if ( MIL == 8 ) {digitalWrite(MIL_PIN,HIGH);} else {digitalWrite(MIL_PIN,LOW);}       EPC=Byte_0x480_1 & B00000100;       if ( EPC == 4 ) {digitalWrite(EPC_PIN,HIGH);} else {digitalWrite(EPC_PIN,LOW);}       CurrentVB=Byte_0x480_2 + (Byte_0x480_3 & B01111111)*256;       }

If you want to know more, here is some additional information.

https://www.canhack.de/en/viewtopic.php?t=2182

Title: On-board computer for the Polo.