MBE 4000 DDEC VI Troubleshooting – Section 50.1 SPN 625/FMI 2

Section 50.1
SPN 625/FMI 2

This fault is typically erratic data or the CAN propriety data link has failed due to no communication between the MCM and the CPC.‪

Note: The following diagnostics pertain to faults received from the MCM and /or the CPC.

Section 50.1.1
Data Link Check

Check as follows:‪

1. Have the MCM and/or the CPC been recently changed or reprogrammed?
   1. If yes, verify the that the correct MCM calibration and/or the correct CPC parameter list has been installed. If the correct calibration and correct parameter list have been installed, go to step 2 .
   2. If no, go to step 2 .
2. Disconnect the MCM 21–pin connector.
3. Turn the ignition ON (key ON, engine OFF).
4. Measure the battery voltage at pin 7 on the MCM 21–pin connector.
   1. If the battery voltage is less than 10.5 volts, restore the battery voltage at pin 7 on the MCM 21–pin connector.

   Note: Poor battery grounds can be a possible cause of low battery voltage.

   2. If the battery voltage is greater than 10.5 volts, go to step 5 .
5. Turn ignition OFF, leave the 21–pin MCM connector disconnected.
6. Disconnect the CPC #4 connector.
7. Measure the resistance between pins 1 and 3 of the CPC #4 connector.
   1. If the resistance is greater than 5 Ω, go to step 8 .
   2. If the resistance is less than 5 Ω, repair the short in the wires between pins 1 and 3 of the CPC #4 connector and pins 13 and 19 of the 21–pin MCM connector. Refer to "51.1.1.1 Verify Repairs" .
8. Measure the resistance between pin 1 of the CPC #4 connector and ground.
   1. If the resistance is greater than 5 Ω, go to step 9 .
   2. If the resistance is less than 5 Ω, repair the short to ground between pin 1 of the CPC #4 connector and ground. Refer to "51.1.1.1 Verify Repairs" .
9. Measure the resistance between pin 3 of the CPC #4 connector and ground.
   1. If the resistance is greater than 5 Ω, go to step 10 .
   2. If the resistance is less than 5 Ω, repair the short to ground between pin 3 of the CPC #4 connector and ground. Refer to "51.1.1.1 Verify Repairs" .
10. Measure the resistance between pin 1 of the CPC #4 connector and pin 19 of the 21–pin MCM connector.
    1. If the resistance is greater than 5 Ω, repair the open between pin 1 of the CPC #4 connector and pin 19 of the 21–pin MCM connector. Refer to "51.1.1.1 Verify Repairs" .
    2. If the resistance is less than 5 Ω, go to step 11 .
11. Measure the resistance between pin 3 of the CPC #4 connector and pin 13 of the 21–pin MCM connector.
    1. If the resistance is greater than 5 Ω, repair the open between pin 3 of the CPC #4 connector and pin 13 of the 21–pin MCM connector. Refer to "51.1.1.1 Verify Repairs" .
    2. If the resistance is less than 5 Ω, call the DDC Customer Support Center (313–592–5800).

Section 50.1.1.1
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.