The connection of NOx sensor to MSD87 is modified – it is significantly different from the solution for E series.


In the picture: sensor power supply and serial interface connection.

NOx sensor connection description

[1] Power supply; +12V
[2] GND; ground
[3] CANL; CAN, Low
[4] CANH; CAN, High
[5] NC; not connected

Unlike for E series, fuse F128 (10A) is intended especially for NOx sensor.


NOx sensor is connected to PT-CAN2 data exchange channel (E series uses special CAN data exchange channel, intended only for this sensor).


In the picture: devices, connected to PT-CAN2:

Following devices are connected to PT-CAN2:

  • DME MSD87
  • gear shift switch (if the vehicle has an automatic transmission)
  • low-pressure fuel pump (it’s management module EKPS)
  • gearbox control module (if the vehicle has an automatic transmission)
  • NOx sensor


Terminal resistors of CAN data exchange channel are placed:

  • DME
  • fuel pump module EKPS (pins 8 and 15)


If the connection with NOx sensor is lost, DME records the error message:

CD8510 Lost Communication With NOx Sensor ‘A’


If DME has recorder error message CD8510, to find the problem:

  • check fuse F128;
  • check the connection of PT-CAN2: when the vehicle is completely turned off (the battery is disconnected), check resistance between Pin 3 and 4. Measured resistance has to be 60 Ohm (+/-10%).


If due to some repair, the low-pressure pump module EKPS is disconnected, it’s necessary to restore performance of PT-CAN2, inserting resistance of 120 Ohm between Pin 9 and 16 in the module socket. If this terminal resistor is not inserted, the performance of PT-CAN2 can be paralyzed (connection with gearbox and it’s selector can be disturbed)