Code B335, Loss Of ECC Serial Data (TORONADO)

This code can only be viewed as a "History" code because if it was "Current Service Diagnostics" it could not be entered. Most likely, the ECC controls for heating and A/C will also be inoperative when the loss of serial data occurs.

Since the serial data lines are redundant, a double open in the circuit No. 800 has to occur to set this code. However, the code will also set for a single open in the power or ground supply to the ECC.

If ECC panel has a current loss of serial data, diagnostics cannot be entered. Current faults are covered on charts C-1 or C-2. Code B335 indicates an intermittent has occurred. Should intermittent problem persist, check the following circuits for opens or poor terminal contacts.

Also check circuit No. 800 between IPC and ECC, including good terminal contact at IPC terminal No. C-4. If intermittent persists, replace ECC. When all diagnosis and repairs are completed, clear codes and verify operation

Fig 1: Code B335, Schematic