MBE 900/4000 SID 243 Troubleshooting

Troubleshooting SID 243

The following steps will troubleshoot SID 243.‪

243 12 – Cruise Control Switch SET and RES Contacts Closed at the Same Time

Perform the following steps to troubleshoot a Cruise Control Switch SET and RES Contacts Closed at the Same Time fault.‪

1. Turn the ignition on and set the cruise control switch to the OFF position. Do not start the engine, since all troubleshooting will be done with the engine off.
2. Note the driver display console.
   1. If the RES status is not displayed, go to step 3 .
   2. If the RES status is displayed, go to step 5 .
3. Check the cruise control switch status.
   1. If the switch status is not displayed as “SET,” contact Detroit Diesel Technical Service.
   2. If the switch status is displayed as “SET,” go to step 4 .
4. Unplug the cruise control switch.
   1. 1. If the status of the SET switch is displayed as “OFF,” replace the cruise control SET/RES switch. Erase fault code memory.
      2. If the status of the SET switch is displayed as “ON,” repair short to ground in 18-pin connector wire 440E. See Figure “Location of DDEC-VCU and Wiring Harness Connectors” for wiring harness connector locations and see Figure “Connector Positions on DDEC-VCU” for connector positions on DDEC-VCU. Erase fault code memory.
   

   1. Passenger-Side Dash‪	4. 18-Pin Connector (VC3)‪
   2. DDEC-VCU‪	5. 21-Pin Connector (VC1)‪
   3. 15-Pin Connector (VC4)‪	‪

   Figure 1. Location of DDEC-VCU and Wiring Harness Connectors

   

   1. 21-Pin DDEC-VCU Connector (VC1)‪	3. 15-Pin DDEC-VCU Connector (VC4)‪
   2. 18-Pin DDEC-VCU Connector (VC3)‪	4. DDEC-VCU‪

   Figure 2. Connector Positions on DDEC-VCU

5. Unplug the RES switch.
   1. If the status of the RES switch is not “RES,” replace the cruise control SET and RES switch. Erase fault code memory.
   2. If the status of the RES switch is “RES,” repair short to ground in 18-pin connector wire 440F. Erase fault code memory. See Figure “Location of DDEC-VCU and Wiring Harness Connectors” for wiring harness connector locations and see Figure “Connector Positions on DDEC-VCU” for connector positions on DDEC-VCU.