DD15 Troubleshooting – Section 35.1 SPN 175/FMI 3

Section 35.1
SPN 175/FMI 3

This diagnosis is typically engine oil temperature circuit failed high.‪

Check as follows:‪

1. Turn the ignition the 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 the next step.
   2. If only fault 175/3 is active, go to step 5 .
3. Disconnect the Fuel Supply Temperature 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 "35.1.1 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 "35.1.1 Verify Repairs" .
5. Disconnect the EOT Sensor.
6. Check the resistance across pins 1 and 2 of the EOT Sensor.
   1. If the resistance is greater than 4 kΩ, replace the sensor. Refer to "35.1.1 Verify Repairs" .
   2. If he resistance is less than 4 kΩ, go to the next step.
7. Turn the ignition On (key ON, engine OFF).
8. Measure the voltage between pins 1 and 2 of the EOT Sensor harness connector.
   1. If the voltage is between 2.75 and 3.24 volts, Refer to "35.1.1 Verify Repairs" .
   2. If the voltage is less than 2.75 volts, go to the next step.
9. Measure the voltage between pin 2 of the EOT Sensor harness connector and ground.
   1. If the voltage is between 2.75 and 3.24 volts, repair the open circuit between pin 1 of the EOT Sensor harness connector and pin 55 of the 120–pin MCM connector. Refer to "35.1.1 Verify Repairs" .
   2. If the voltage is less than 2.75 volts, repair the open circuit between pin 2of the EOT Sensor harness connector and pin 108 of the 120–pin MCM connector. Refer to "35.1.1 Verify Repairs" .

Section 35.1.1
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.

   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.