Series 60 DDEC VI Troubleshooting – Section 34.1 SPN 174/FMI 3

Section 34.1
SPN 174/FMI 3

SPN 174/FMI 3 indicates a SFT Sensor open circuit or short to power.‪

Section 34.1.1
Open Circuit/Short to Power Check

Check as follows:‪

  1. Turn the ignition ON (key ON, engine OFF).
  2. Check for multiple codes.
    1. If codes 110/3, 174/3, 175/3 and 3510/3 are active at the same time, go to step 3 .
    2. If only fault 174/3 is active, go to step 5 .
  3. Disconnect the Supply Fuel Temperature Sensor (ECT Sensor).
  4. Measure the voltage between pin 1 of the SFT Sensor and ground.
    1. If the voltage is greater than 2.75 volts, repair the short to power between pin 55 of the MCM 120–pin connector and the Engine Coolant Temperature Sensor, the Engine Oil Temperature Sensor and the Supply Fuel Temperature Sensor. Refer to "34.1.1.1 Verify Repairs" .
    2. If no voltage is present on pin 1 of the SFT Sensor, repair the open between pin 55 of the MCM 120–pin connector and the Engine Coolant Temperature Sensor, the Engine Oil Temperature Sensor and the Supply Fuel Temperature Sensor. Refer to "34.1.1.1 Verify Repairs" .
  5. Disconnect the SFT Sensor.
  6. Measure the resistance across pins 1 and 2 of the SFT Sensor. See Figure "Supply Fuel Temperature Sensor" .
    Click to see this graphic in a separate window

    Figure 1. Supply Fuel Temperature Sensor

    1. If the resistance is greater than 4k Ω, replace SFT Sensor. Refer to "34.1.1.1 Verify Repairs" .
    2. If the resistance is less than 4k Ω, go to step 7 .
  7. Turn the ignition ON (key ON, engine OFF).
  8. Measure the voltage between pins 1 and 2 of the SFT Sensor harness connector.
    1. If the voltage is between 2.75 and 3.25 volts, refer to "34.1.1.1 Verify Repairs" .
    2. If the voltage is less than 2.75 volts, go to step 9 .
  9. Measure the voltage between pin 2 of the SFT Sensor harness connector and ground.
    1. If the voltage is between 2.75 and 3.25 volts, repair the open circuit between pin 1 of the SFT Sensor harness connector and pin 55 of the 120–pin MCM connector.See Figure "MCM 120–pin Connector" . Refer to "34.1.1.1 Verify Repairs" .
    2. If the voltage is less than 2.75 volts, repair the open circuit between pin 2 of the SFT Sensor harness connector and pin 77 of the 120–pin MCM connector.See Figure "MCM 120–pin Connector" . Refer to "34.1.1.1 Verify Repairs" .
    3. Click to see this graphic in a separate window

      Figure 2. MCM 120–pin Connector

Section 34.1.1.1
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.


EPA07 Series 60 DDEC VI Troubleshooting Guide - 6SE567
Generated on 10-13-2008

Leave a Reply

Your email address will not be published. Required fields are marked *