VW Dashboard CAN controller (Based on Arduino Micro and MCP2515)

Arduino and MCP2515 based controller for a 2018 Volkswagen UP instrument cluster (part number: 1S0.920.870.C). Various instrument cluster functions are controlled by sending command strings over the USB serial port, which get then translated in to appropriate CAN messages that get periodically sent to the instrument cluster.

Command string structure:

<sub_cmd1>=<parameter>;<sub_cmd2>=<parameter>;<sub_cmd3>;\n

Command string description:

Command string ends with "\n" (newline) character
Command string consists of sub commands ending with ";"
Each sub command can have a parameter separated from the sub command by "=" character
Maximum command string length is 64 characters

Example command string:

v=100;r=2500;c=3.14;ID;\n

Sub command 1: v=100; -> Command: v, Parameter: 100 (type int)
Sub command 2: r=2500; -> Command: r, Parameter: 2500 (type int)
Sub command 3: c=3.14; -> Command: c, Parameter: 3.14 (type float)
Sub command 4: ID; -> Command: ID, Parameter: None

Available commands (and parameters):

ID: Print ID string (Parameter: NONE)
v: Set vehicle speed (Parameter: vehicle speed in [km/h])
r: Set engine speed (Parameter: engine speed in [RPM])
c: Set Fuel consumption (Parameter: fuel consumption in [ml/s], type float)
F: Set Fuel level (Parameter: 0...Empty, 100...Full)
Tc: Set coolant temperature (Parameter: temperature in [°C])
To: Set oil temperature (Parameter: temperature in [°C])
t: Turn signal indicators (Parameter: 0...OFF, 1...LEFT, 2...RIGHT, 3...BOTH)
f: Fog Light indicator (Parameter: 0...OFF, 1...ON)
h: High Beam indicator (Parameter: 0...OFF, 1...ON)
CC: Cruise control indicator (Parameter: 0...OFF, 1...ON)
BW: Battery Warning indicator (Parameter: 0...OFF, 1...ON)
TP: Tire Pressure indicator (Parameter: 0...OFF, 1...ON)
EPC: EPC Warning indicator (Parameter: 0...OFF, 1...ON)
DPF: DPF Warning indicator (Parameter: 0...OFF, 1...ON)
b: Seat belt indicator (Parameter: 0...OFF, 1...ON)
D: Open Door indicator (Parameter: Bit0...FL, Bit1...FR, Bit2...RL, Bit3...RR, Bit4...Engine Cover, Bit5...Trunk)
p: Switched power control (Parameter: 0...OFF, 1...ON)
M: Display message on screen (Parameter: MESSAGE_ID, see Available Message IDs below)
BL: Set backlight level (Parameter: level 1=MIN...100=MAX and 0=AUTO)

Available Display Message IDs:

0 ... No message
1 ... Start/Stop Icon
2 ... Start/Stop Error
3 ... Start Engine Manually
5 ... Start/Stop Disabled
12 ... Engine Starting
13 ... Depress Clutch
14 ... Move selector lever to position P/N
15 ... Apply Break

List of used CAN messages

The following list of CAN messages has been tested on a 2018 Volkswagen UP instrument cluster (part number: 1S0.920.870.C). This list is by no means complete but should be more than enough to control basic functionality of said instrument cluster.

To avoid the "Check Engine" warning light coming on and staying on, at least the engine RPM (0x280) and vehicle speed (0x5A0) CAN messages should start sending periodically when the instrument cluster switched power +12V_SW turns on (Standby power +12V_SB should already be on or come on with switched power rail).

Engine RPM

Message ID: 0x280
Message content: {0x49, 0x0E, LSB(AA), MAB(AA), 0x0E, 0x00, 0x1B, 0x0E}

Engine RPM:

16bit value: AA = n[RPM] * 4

Speedometer and distance counter

Message ID: 0x5A0
Message content: {0xFF, LSB(AA), MSB(AA), CC, 0x00, LSB(BB), MSB(BB), 0xAD}

Speedometer:

16bit value: AA = v[km/h] * 148

Distance counter:

16bit counter: BB
50 counts per 1m travel distance
Counter overflow at 30000
Should be incremented according to current speed value in order for the speedometer to work properly

Tire pressure warning light:

Bitfield: CC
Bit 3: Tire pressure warning light

Fuel consumption and some engine warning lights

Message ID: 0x480
Message content: {0x00, BB, MSB(AA), LSB(AA), 0x00, 0xCC, 0x00, 0x00}

Fuel consumption:

16bit counter: AA
1 count per 0,25 ml of fuel consumed
Displayed consumption value gets calculated based on the counting rate of the counter and current speedometer value
Should be updated periodically for a stable fuel consumption reading

Warning lights:

Bitfield: BB
Bit 2: "EPC" warning light
Bit 4: Coolant warning light
Bitfield: CC
Bit 1: Exhaust particle filter warning light

Body lights indicators and open door status

Message ID: 0x470
Message content: {AA, BB, CC, 0x00, 0x00, FF, 0x00, HH}

Turn signal indicators and battery warning:

Bitfield: AA
Bit 0: Left Turn signal
Bit 1: Right Turn signal
Bit 7: Battery warning light

Door status:

Bitfield: BB
Bit 0: Front Left
Bit 1: Front Right
Bit 2: Rear Left
Bit 3: Rear Right
Bit 4: Engine cover
Bit 5: Trunk

Instrument cluster backlight:

8bit value: CC
Automatic backlight control: C = 0
Manual backlight control: C = 1(min) ... 100(max)

Key battery warning:

Bitfield: FF
Bit 7: Display "Low key battery" warning message

High beam and fog lights:

Bitfield: HH
Bit 5: High beam indicator light
Bit 6: Fog light indicator light

Coolant temperature reading and cruise control indicator light

Message ID: 0x288
Message content: {0x00, AA, BB, 0x00, 0x00, 0x00, 0x00, 0x00}

Coolant temperature:

8bit value: AA
Displayed value is not linear with input value AA
Displayed value in 5°c increments
AA = 0x01 ... T_coolant = -45°c (minimum display value)
AA = 0x08 ... T_coolant = -40°c
AA = 0x0E ... T_coolant = -35°c
AA = 0x15 ... T_coolant = -30°c
AA = 0x1C ... T_coolant = -25°c
AA = 0x22 ... T_coolant = -20°c
AA = 0x29 ... T_coolant = -15°c
AA = 0x30 ... T_coolant = -10°c
AA = 0x36 ... T_coolant = -5°c
AA = 0x3D ... T_coolant = 0°c
AA = 0x4A ... T_coolant = 10°c
AA = 0x58 ... T_coolant = 20°c
AA = 0x66 ... T_coolant = 30°c
AA = 0x72 ... T_coolant = 40°c
AA = 0x80 ... T_coolant = 50°c
AA = 0x85 ... T_coolant = 55°c
AA = 0x89 ... T_coolant = 60°c
AA = 0x92 ... T_coolant = 70°c
AA = 0x9A ... T_coolant = 80°c
AA = 0xA2 ... T_coolant = 90°c
AA = 0xD4 ... T_coolant = 100°c
AA = 0xD7 ... T_coolant = 105°c
AA = 0xDB ... T_coolant = 110°c (coolant warning light turns off)
AA = 0xDE ... T_coolant = 115°c
AA = 0xE1 ... T_coolant = 120°c
AA = 0xE6 ... T_coolant = 125°c (coolant warning light turns no)
AA = 0xE8 ... T_coolant = 126°c
AA = 0xE9 ... T_coolant = 127°c
AA = 0xEA ... T_coolant = 128°c
AA = 0xEC ... T_coolant = 129°c
AA = 0xED ... T_coolant = 130°c (maximum display value)

Cruise control indicator:

Bitfield: BB
Bit 6: Cruise control indicator light (XOR logic with bit 7)
Bit 7: Cruise control indicator light (XOR logic with bit 6)

Oil temperature reading:

Message ID: 0x588
Message content: {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, AA}

Oil temperature:

8Bit value: AA = T_oil[°c] + 60
Minimum: T_oil = 50°c
Maximum: T_oil = 194°c

Airbag and seatbelt warnings

Message ID: 0x050
Message content: {0x00, AA, BB, 0x00, 0x00, 0x00, 0x00, 0x00}

Airbag warnings:

Bitfield: AA
Bit 0: Airbag warning light
Bit 1: Display "Airbag, Belt tensioner disabled" message
Bit 3: Display "Airbag Error# message
Bit 5: Seatbelt warning light

Seatbelt warnings:

Bitfield: BB
Bit 2: Seatbelt warning light

Start/Stop system messages:

Message ID: 0x58C
Message content: {AA, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, BB}

Start/Stop system message:

Message ID: AA
AA = 0x01: Display start/stop icon
AA = 0x02: Display start/stop error
AA = 0x03: Display "Start Engine Manually" message
AA = 0x05: Display "Start/Stop Disabled" message
AA = 0x0C: Display "Engine Starting" message
AA = 0x0D: Display "Depress Clutch" message
AA = 0x0E: Display "Move selector lever to position P/N" message
AA = 0x0F: Display "Apply Break" message

Break pedal warning light:

Bitfield: BB
Bit 0: Green Break Pedal Warning light

Other functions

There are some functions, that are not controlled by sending CAN messages, instead they are controlled directly by input signals on the instrument cluster IO port.

Switched power

Instrument cluster has two 12V power inputs:

Main power +12V_PWR: IO Pin 32
Switched power +12V_SW: IO Pin 31

Switched power input is used to switch between STANDBY and ON states of the instrument cluster, while the main power input serves as power supply rail (+12V) for the instrument cluster. Most of the instrument cluster functions only work in ON mode when switched power input is high (+12V).

Fuel level gauge

Fuel level gauge is controlled by two input signals:

FuelGaugeF: IO Pin 1
FuelGaugeE: IO Pin 2

A resistor chain (or a potentiometer) is connected between the two inputs. Fuel level is set by grounding the resistor chain somewhere between the two inputs (see schematic)