MBE 900 DDEC VI Troubleshooting – Section 80.3 SPN 1072/FMI 5

Section 80.3
SPN 1072/FMI 5

This diagnosis is typically the Constant Throttle Valve circuit failed open‪

Section 80.3.1
Open Circuit Check

Check as follows:‪

1. Check for multiple codes.
   1. If 3471/5 and 3482/5 are active with 1072/5, repair the open between pin 64 of the 120–pin MCM connector and pin 2 of the Constant Throttle Valve and pin 2 of the Electronic Dosing Valve connector and pin 2 of the Fuel Shutoff Valve. See Figure "Constant Throttle Valve" . Refer to "80.2.1.1 Verify Repairs" .
      

      Figure 1. Constant Throttle Valve

   2. If only 1072/5 is active, go to step 2 .
2. Disconnect the Constant Throttle Valve connector.
3. Turn the ignition ON (key ON, engine OFF).
4. Measure the voltage between pins 1 and 2 of the Constant Throttle Valve connector.
   1. If the voltage is between 11 and 13 volts, replace the Constant Throttle Valve.
   2. If the voltage is less than 11 volts, go to step 5 .
5. Measure the voltage between pin 2 of the Constant Throttle Valve connector and ground.
   1. If the voltage is between 11 and 13 volts, repair the open in the wire between pin 32 of the 120–pin MCM connector and pin 1 of the Constant Throttle Valve connector. See Figure "Constant Throttle Valve" . Refer to "80.3.1.1 Verify Repairs" .
   2. If the voltage is less than 11 volts, repair the open in the wire between pin 64 of the 120–pin MCM connector and pin 2 of the Constant Throttle Valve connector. See Figure "Constant Throttle Valve" . Refer to "80.3.1.1 Verify Repairs" .

Section 80.3.1.1
Verify Repairs

Verify repairs as follows:‪

1. Turn ignition OFF.
2. Reconnect any electrical connections that were disconnected to perform the diagnosis.
3. Clear codes with DDDL 7.0 or latest version.
4. Start and bring engine up to operating temperature (over 140°F/60°C).
5. Verify operation is satisfactory and no warning lamps illuminate. If warning lamps illuminate, troubleshoot the codes. If assistance is required, call the Detroit Diesel Customer Support Center at 313–592–5800.