MBE 4000 DDEC VI Troubleshooting – Section 56.2 SPN 651/FMI 14

Section 56.2
SPN 651/FMI 14

This diagnosis is typically an open circuit, short to ground or short to power.‪

Section 56.2.1
Open Circuit, Short to Ground or Short to Power Check

Check as follows:‪

1. Check for multiple codes.
   1. If 651/14, 652/14 and 653/14 are present, go to step 2 .
   2. If only 651/14 is present, go to step 6 .
2. Turn the ignition OFF.
3. Disconnect the MCM 120–pin connector (if using the J-48475 breakout box and appropriate overlay, only hook-up the MCM side connector).
4. Turn the ignition ON (key ON, engine OFF).
5. Measure the voltage between pin 27 of the MCM 120–pin connector and ground. See Figure "Injector #1" .
   1. If voltage is present, contact the Detroit Diesel Customer Support Center at 313–592–5800 for authorization to replace the MCM.
   2. If no voltage is present, repair the short to power between pins 23, 25 or 27 of the MCM 120–pin connector and injector #1, #2 or #3. Refer to "56.2.1.1 Verify Repairs" .
   

   Figure 1. Injector #1

6. Turn the ignition OFF.
7. Remove the valve cover for cylinder #1
8. Measure the resistance between pins 1 and 2 on the adaptor frame.
   1. If the resistance is greater than 3 Ω, go to step 9 .
   2. If the resistance is less than 3 Ω, go to step 10 .
9. Measure the resistance between pins 1 and 2 of injector #1.
   1. If the resistance is greater than 3 Ω, replace the injector. Refer to "56.2.1.1 Verify Repairs" .
   2. If the resistance is less than 3 Ω, replace the adaptor frame. Refer to "56.2.1.1 Verify Repairs" .
10. Disconnect the MCM 120–pin connector.
11. Measure the resistance between pin 1 of the adaptor frame and pin 27 of the MCM 120–pin connector.
    1. If the resistance is greater than 3 Ω, repair the open circuit between pin 1 of the adaptor frame and pin 27 of the MCM 120–pin connector. Refer to "56.2.1.1 Verify Repairs" .
    2. If the resistance is less than 3 Ω, repair the open circuit between pin 2 of the adaptor frame and pin 26of the MCM 120–pin connector. Refer to "56.2.1.1 Verify Repairs" .

Section 56.2.1.1
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.