MBE 4000 DDEC VI Troubleshooting – Section 29.3 SPN 110/FMI 3

Section 29.3
SPN 110/FMI 3

SPN 110/FMI 3 indicates that the Engine Coolant Temperature Sensor (ECT Sensor) input to the MCM has exceeded 95% of the sensor supply voltage. The diagnostic condition is typically engine coolant temperature open circuit (110/3). ‪

Section 29.3.1
Multiple Code Check

as follows:‪

1. Turn the ignition ON (key ON, engine OFF).
2. Plug in the diagnostic tool.
3. Read the active codes.

Section 29.3.2
Open Circuit Check

Check as follows:‪

1. Check for multiple codes.
   1. If codes 110/3, and 174/3 are present, repair the open circuit between pin 55 of the 120–pin MCM connector and the ECT Sensor and the Supply Fuel Temperature Sensor. Refer to "29.3.1.1 Verify Repairs" .
   2. If SPN 113/0, 174/3, 175/3 and 1636/3 are present, go to step 4 .
   3. If only fault 110/3 is active, go to the next step.
2. Disconnect the ECT Sensor.
3. Measure the resistance across pins 1 and 2 of the ECT Sensor. See Figure "ECT Sensor" .
   

   Figure 1. ECT Sensor

   1. If the resistance is greater than 4k Ω, replace the sensor. Refer to "29.3.1.1 Verify Repairs" .
   2. If the resistance is less than 4k Ω, repair the open circuit between pin 110 of the MCM 120–pin connector and pin 2 of the ECT Sensor harness connector. Refer to "29.3.1.1 Verify Repairs" .
4. Turn the ignition OFF.
5. Disconnect the MCM 120–pin connector.
6. Connect ONLY the MCM side of the J48475 breakout box.
7. Turn the ignition ON (key ON, engine OFF).
8. Measure the voltage between pins 77, 106, 108, 110 of the MCM 120–pin connector and ground.
   1. If the voltage is greater than 3.5 volts on any of these pins, contact the Detroit Diesel Customer Support Center at 313–592–5800.
   2. If the voltage is 3 volts, go to step 6 .
9. Turn the ignition OFF.
10. Reconnect the 120–pin MCM connector.
11. Turn the ignition ON (key ON, engine OFF).
12. Monitor the active faults.
13. Disconnect the ECT Sensor.
    1. If the faults become inactive, replace the ECT Sensor. Refer to "29.3.1.1 Verify Repairs" .
    2. If the faults are still active, go to the next step.
14. Disconnect the Supply Fuel Temperature Sensor.
    1. If the faults become inactive, replace the Supply Fuel Temperature Sensor. Refer to "29.3.1.1 Verify Repairs" .
    2. If the faults are still active, go to the next step.
15. Disconnect the Engine Oil Temperature Sensor.
    1. If the faults become inactive, replace the Engine Oil Temperature Sensor. Refer to "29.3.1.1 Verify Repairs" .
    2. If the faults are still active, go to the next step.
16. Disconnect the Intake Air Temperature Sensor.
    1. If the faults become inactive, replace the Intake Air Temperature Sensor. Refer to "29.3.1.1 Verify Repairs" .
    2. If the faults are still active, repair the short to power on pins 77, 106, 108, 110 of the MCM 120–pin connector and their associated sensors. Refer to "29.3.1.1 Verify Repairs" .

Section 29.3.2.1
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.