VW e-Up via Comfort CAN (T26A)

Vehicle Type: integrated in VWUP

This part was the initial code for the OVMS VWUP vehicle module. Development started in January 2020 by Chris van der Meijden.

It supports the VW e-UP (2013-, 2020-), Skoda Citigo E IV and the Seat MII electric (2020-) directly connected to the comfort can bus through the ‘T26A’ socket.

Support Overview

Function Support Status
Hardware Any OVMS v3 (or later) module. Vehicle support: 2020- (2013- VW e-Up as well)
Vehicle Cable Comfort CAN T26A (OCU connector cable, located under front passenger seat) to DB9 Data Cable for OVMS using pin 6 and 8 for can3
GSM Antenna T4AC - R205 with fakra_sma adapter cable or 1000500 Open Vehicles OVMS GSM Antenna (or any compatible antenna)
GPS Antenna T4AC - R50 with fakra_sma adapter cable or 1020200 Universal GPS Antenna (or any compatible antenna)
SOC Display Yes
Range Display Yes
Cabin Pre-heat/cool Control Yes
GPS Location Yes (from modem module GPS)
Speed Display Yes
Temperature Display Yes (outdoor, cabin)
BMS v+t Display No
TPMS Display No
Charge Status Display Yes
Charge Interruption Alerts Yes (per notification on the charging state)
Charge Control tba
Lock/Unlock Vehicle No
Valet Mode Control No
Others Odometer, trip, VIN, status of lock, plug, lights, doors, trunk and bonnet

Pinout OCU T26A - OVMS DB9 adapter

For the T26A approach we directly tap into the comfort can bus via the original OCU cable.

The OCU connector is located under the passenger seat.


Advantage is the direct write access to the comfort can bus.

Disadvantage is that we won’t be able to access all control units of the car.

OCU DB9-F Signal
26 3 Chassis / Power GND
. 2 can1 L (Can Low, not used)
. 7 can1 H (Can High, not used)
. 4 can2 L (Can Low, not used)
. 5 can2 H (Can High, not used)
2 6 can3 L (Comfort-can Low)
14 8 can3 H (Comfort-can High)
1 9 +12V Vehicle Power

For confectioning the T26A adapter cable you can use a standard 26 pin ribbon cable (2x13 pins, 2,54mm grid dimension) and a DB9 female D-Sub connector. You will need to grind down the rim of the socket of the ribbon cable.

To make a GSM/GPS adapter cable to connect to the original VW fakra socket you can use a double fakra male connector with two SMA male connectors attached.

../../../_images/grinded_ribbon.png ../../../_images/fakra_sma.png

User notes

  • Remove the passenger seat (on right hand drive cars the driver’s seat).
  • Open the carpet lid.
  • Disconnect the T26A cable and the fakra cable from the OCU (online communication unit).
  • Remove the OCU.
  • Connect the confectioned T26A adapter DB9 cable attached to the OVMS to the VW T26A connector of the car.
  • Connect your GMS/GPS fakra adapter to the VW fakra cable.
  • Fit OVMS in the compartment.
  • Close the carpet lid.
  • Reinstall the passenger seat.
  • Configure OVMS as described in the OVMS user manual.
  • Configure ‘Model year’, ‘Can write access’ and ‘Connection type’ under VW e-Up -> Features.
  • ‘Model year’ and ‘Can write access’ can also be set from within the app (FEATURES 20 and 15).
  • Register and connect OVMS to a server (as guided within the OVMS setup).
  • Turn the ignition in the car on and off to receive initial values (also needed after updates).
  • Install the OVMS app on your smartphone or tablet and configure it to connect to the server.
  • Enjoy :-)

Climate control

Climate control works, as long as write access to the comfort can has been enabled in the app or in the OVMS webinterface (VW e-Up -> Features).

To turn on or off the AC from within the Android app just press the “A/C” button. Within the iOS app press “Homelink 1” for AC on and “Homelink 2” for AC off.

Once the AC is turned on by the app there will be a delay of about 17 seconds untill the AC actually starts in the car. Further 10 seconds all communication from the app to the car is blocked.

The communication from the app to the car is also blocked for 10 seconds after the “AC off” command from the app to the car. There is no delay between the “AC off” signal of the app and the actually turning off in the car.

In rare cases ‘AC off’ does not respond. There will be a delay of 40 seconds before you can try again.

The cabin target temperature can be set from the OVMS webinterface (VW e-Up (Komfort CAN) -> Climate control) or via the app under FEATURES 21.


IDs on Comfort CAN Bus

ID Conversion Unit Function
61A d7/2 % State of Charge (relative)
320 (d4<<8+d3-1)/190 km/h Speed
65F 3 Msg d5-7,d1-7,d1-7 String VIN number
571 5+(.05*d0) Volt 12 Volt battery voltage
65D d3&f<<12|d2<<8|d1 km Odometer
3E3 (d2-100)/2 °C Cabin temperature
527 (d5/2)-50 °C Outdoor temperature
531 d0 00   Headlights off
52D d0 +255 if d1 41 km Calculated range
381 d0 02   Status doors locked
470 d1 1,2,4,8,20,10   Integer Doors, trunk, hood opened or closed
3E1 d4   Integer Blower speed?(57,66,7D,98,BB,DE,FA)
575 d0 00 to 0F   Integer Key position
575 d3 00 or 10   windshield heater (off or on)
569 b07   “AC”-LED
69C d1/10+10 °C temperature setpoint for remote AC (only in message D2 <d1> 00 1E 1E 0A 00 00)
61C d2 < 07 bool Charging detection
43D d1 01 or 11   TX: Working or sleeping in the ring
5A7 d1 16   TX: OCU AC blocking signal
5A9 all 00   TX: OCU heartbeat
69E multiple msg d0 C1 d6 xx °C TX: AC on / off signals TX: set cabin temperature for 69C

Development notes

Under this vehicle component part we use the original T26A approach, which can write to the comfort can and is able to manage the climate control of the car.

You will normally use the OVMS binaries provided i.e. here.

The VWUP T26A component part with working climate control is publicly available within the OVMS binary version 3.2.15 ‘edge’ and upwards (‘main’, ‘eap’ and ‘edge’). The Android app version has to be 3.17.1 or higher to have access to the climate control functions for this vehicle component.

If you want to compile the binary yourself you will need to read the OVMS development documentation on how to set up the tool chain, check out the repository and the submodules and copy the file


from the OVMS.V3/support folder to the OVMS.V3 folder and rename it to


Vehicle log files

To be able to implement the VWUP vehicle component for OVMS the CAN logging of the VW e-UP provided by ‘sharkcow’ was of tremendous help.

The implementation of this vehicle component could not have been done without these great files.

They can be found here: