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
 Power supply; +12V
 GND; ground
 CANL; CAN, Low
 CANH; CAN, High
 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:
- 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)