TM9-2320-360-20-3 Section 4 TROUBLESHOOTING CHARTS D. CHART -7 - NO DATA TO DDR (Cont’d) STEP/SEQUENCE C7-4 Check  for  Open  Light l Turn  off  ignition. l   Place a jumper wire across pins - A (#900) and B (#901) of DDL connector. l Unplug  vehicle  harness  connector and  measure  resistance  between sockets  C1  and  C2. C 7-6 Check  for  Short l   Remove jumper wire from DDL connector. l Read  resistance  between  sockets Cl  (#901)  and  C2  (#900) of  vehicle  harness  connector. C7-6 Check for Short to ignition  and Ground l   Remove  all  jumpers  from  the  DDL connector. l Measure   resistance   between socket  A  (#900)  and  E  (ground), A (#900) and C (sw-ign), B (#901) and E (ground), and B (#901) and C (sw-ign) of DDL connector. C  7-7 Check  DDR  on Another Engine l Connect  DDR  to  another  engine and read any parameter  in  menu. RESULT WHAT  TO  DO  NEXT Greater  than 5  ohms. One or both data wires (Ckt #900 or  #901)  is  open.  Repair  open and  go  to  C7-30. Less  than 5 ohms. Two  data  wires  are  shorted together (ckt #900 and #901). Repair  short  and  go  to  C7-30. Go to C 7-6. A short exists between a data wires  and  ignition  or  ground. Repair  short  and  go  to  C7-30. Go to C 7-7. Works  okay. Does  not  work. Go  to  C7-30. DDR  is  probably  defective.  Bee DDR  instruction  manual  for repair. H-81