MBE 900 DDEC VI Troubleshooting – Section 82.3 SPN 1172/FMI 4

Section 82.3
SPN 1172/FMI 4

This code is typically sensor or circuit failed low.‪

Section 82.3.1
Short Circuit Check

Check as follows:‪

1. Place ignition switch in the OFF position.
2. Disconnect the 31–pin connector.
3. Disconnect the TCI Sensor.
4. Measure resistance between pin 27 and pin 28 of the 31–pin connector on the vehicle side.
   1. If the resistance is less than 10 Ω, repair the short between pin 27 and pin 28 of the 31–pin connector. Refer to "82.3.1.1 Verify Repairs" .
   2. If the resistance is greater than 10 Ω, go to step 5 .
5. Measure resistance between pin 27 of the 31–pin connector and ground on the vehicle side.
   1. If the resistance is less than 5 Ω, repair the short to ground between pin 27 of the 31–pin connector and pin 1 of the TCI Sensor. Refer to "82.3.1.1 Verify Repairs" .
   2. If the resistance is greater than 5 Ω, go to step 6 .
6. Measure resistance between pin 28 and ground on the vehicle side.
   1. If the resistance is less than 5 Ω, repair the short to ground between pin 28 of the 31–pin connector and pin 2 of the TCI Sensor. Refer to "82.3.1.1 Verify Repairs" .
   2. If the resistance is greater than 5 Ω, go to step 7 .
7. Disconnect the 120–pin MCM connector.
8. Measure resistance between pin 27 and pin 28 of the 31–pin connector on the engine side.
   1. If the resistance is less than 10 Ω, repair the short between pin 27 and pin 28 between the 31–pin connector and the 120–pin MCM connector. Refer to "82.3.1.1 Verify Repairs" .
   2. If the resistance is greater than 10 Ω, go to step 9 .
9. Measure resistance between pin 27 of the 31–pin connector and ground on the engine side.
   1. If the resistance is less than 5 Ω, repair the short to ground between pin 27 of the 31–pin connector and ground. Refer to "82.3.1.1 Verify Repairs" .
   2. If the resistance is greater than 5 Ω, go to step 10 .
10. Measure resistance between pin 28 of the 31–pin connector and ground on the engine side.
    1. If the resistance is less than 5 Ω, repair the short to ground between pin 28 of the 31–pin connector and ground. Refer to "82.3.1.1 Verify Repairs" .
    2. If the resistance is greater than 5 Ω, contact the Detroit Diesel Customer Support Center (313–592–5800) for authorization to replace the MCM.

Section 82.3.1.1
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.