DD15 Troubleshooting – Section 34.3 SPN 174/FMI 4

Section 34.3
SPN 174/FMI 4

SPN 174, PID 174/FMI 4 indicates a SFT Sensor short circuit to ground.‪

Check as follows:‪

1. Disconnect the SFT Sensor.
2. Disconnect the 120-pin MCM connector.
3. Measure the resistance across pins 1 and 2 of the SFT Sensor connector.
   1. If resistance is less than 5 Ω, repair short between wires 55 and 77 of the 120-pin MCM connector. Refer to "34.3.1 Verify Repairs" .
   2. If resistance is greater than 5 Ω, go to the next step.
4. Measure the resistance between pin 1 of the SFT Sensor harness connector and ground.
   1. If resistance is less than 5 Ω, repair the short circuit between pin 1 of the SFT Sensor harness connector and ground. Refer to "34.3.1 Verify Repairs" .
   2. If resistance is greater than 5 Ω, go to the next step.
5. Measure the resistance between pin 2 of the SFT Sensor harness connector and ground.
   1. If resistance is less than 5 Ω, repair the short circuit between pin 2 of the SFT Sensor harness connector and ground. Refer to "34.3.1 Verify Repairs" .
   2. If resistance is greater than 5 Ω, review steps 3 through 5 . If the results are the same, contact Detroit Diesel Customer Support Center at 313-592-5800.

Section 34.3.1
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.

   ENGINE EXHAUST ‪
   To avoid injury from inhaling engine exhaust, always operate the engine in a well-ventilated area. Engine exhaust is toxic.‪

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.