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.
52.1.1
Data Link Check
Check as follows:
1. Have the MCM and/or the CPC been recently changed or reprogrammed?
[a] 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 the next step.
[b] If no, go to the next step.
2. Disconnect the MCM 21–pin connector.
3. Turn the ignition ON (key ON, engine OFF).
4. Measure the ignition voltage at pin 7 on the MCM 21–pin connector.
[a] If the ignition voltage is less than 10.5 volts, restore the ignition voltage at pin 7.
Refer to section 52.1.1.1.
[b] If the ignition voltage is greater than 10.5 volts, go to the next step.
5. Measure the battery voltage at pins 11, 12, 14, and 15 on the MCM 21–pin connector.
[a] If the battery voltage is less than 10.5 volts, restore the battery voltage at pins 11, 12,
14, and 15 on the MCM 21–pin connector. Refer to section 52.1.1.1.
NOTE:
Poor battery grounds can be a possible cause of low battery voltage.
[b] If the battery voltage is greater than 10.5 volts, go to the next step.
6. Turn ignition OFF, leave the 21–pin MCM connector disconnected.
7. Disconnect the CPC #4 connector.
8. Measure the resistance between pins 1 and 3 of the CPC #4 connector.
[a] If the resistance is greater than 5 Ω, go to the next step.
[b] If the resistance is less than 5 Ω, repair the short circuit 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 section 52.1.1.1.
9. Measure the resistance between pin 1 of the CPC #4 connector and ground.
[a] If the resistance is greater than 5 Ω, go to the next step.
[b] If the resistance is less than 5 Ω, repair the short circuit to ground between pin 1 of
the CPC #4 connector and ground. Refer to section 52.1.1.1.
10. Check the resistance between pin 3 of the CPC #4 connector and ground.
[a] If the resistance is greater than 5 Ω, go to the next step.
[b] If the resistance is less than 5 Ω, repair the short circuit to ground between pin 3 of
the CPC #4 connector and ground. Refer to section 52.1.1.1.
11. Measure the resistance between pin 1 of the CPC #4 connector and pin 19 of the 21–pin MCM connector.
[a] If the resistance is greater than 5 Ω, repair the open circuit between pin 1 of the CPC
#4 connector and pin 19 of the 21–pin MCM connector. Refer to section 52.1.1.1.
[b] If the resistance is less than 5 Ω, go to the next step.
12. Measure the resistance between pin 3 of the CPC #4 connector and pin 13 of the 21–pin MCM connector.
[a] If the resistance is greater than 5 Ω, repair the open circuit between pin 3 of the CPC
#4 connector and pin 13 of the 21–pin MCM connector. Refer to section 52.1.1.1.
[b] If the resistance is less than 5 Ω, call the DDC Customer Support Center (313–592–5800).
52.1.1.1
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.
