Test results

Check that the CAN connections between the supplementary heater control unit and the Body Computer are not faulty. In particular, that there are no open circuit or short circuit problems

 See E1050 CAN CONNECTION LINES

Go to Step 2

There are faulty connections

Restore or, if necessary, replace the wiring

Check the Body Computer power supply is correct.

Go to Step 3

Power supply not correct

Restore the correct power supply.

Replace supplementary heater control unit

 Op. 5020E60 ADDITIONAL HEATER P.T.C. - R.R.

and check it is working correctly

End of diagnosis

The fault persists.

Go to Step 4

Replace the Body Computer

 Op. 5505A35 MAIN BODY COMPUTER/JUNCTION UNIT - R.R.

End of diagnosis