Section 26.1
SPN 100/FMI 1

SPN 100/FMI is typically low engine oil pressure.‪

Section 26.1.1
Low Oil Pressure Check

Check as follows:‪

1. Check for multiple codes.
   1. If fault codes 100/1 and 100/3 are both active, refer to "26.2.1 Failed High Circuit Check" .
   2. If fault codes 100/1 and 100/4 are both active, refer to "26.3.1 Failed Low Circuit Check"
   3. If only fault code 100/1 is active, go to step 2 .
2. Observe the stability of the oil pressure.
   1. If the oil pressure is in normal operating range and stable, go to step 3 .
   2. If the oil pressure is fluctuating, go to step 4 .
3. Check the oil level.

   Note: An increase in the engine oil level indicates fuel may be leaking into the engine oil.

   1. If the oil level is high, check for fuel entering into the engine oil system and repair as required. Change the engine oil. Refer to "26.1.1.1 Verify Repairs" .
   2. If the engine oil level is low, fill oil to proper level. Refer to "26.1.1.1 Verify Repairs" .
4. Check the operation of the oil gage.
   1. If the oil gage readings are erratic, repair or replace the oil gage as required.Refer to "26.1.1.1 Verify Repairs" .
   2. If the oil gage readings are fine, go to step 5 .
5. Check the condition of the oil pump suction pipe.
   1. If the pipe is loose or cracked, replace a cracked pipe and reinstall a loose pipe. Refer to "26.1.1.1 Verify Repairs" .
   2. If there is no problem with the oil pump suction pipe, go to step 6 .
6. Check the condition of the oil pump drive and driven gears.
   1. If either gear is loose, repair or replace loose gears as required. Refer to "26.1.1.1 Verify Repairs" .
   2. If neither gear is loose, go to step 7 .
7. Check for a faulty oil pressure relief valve.
   1. If the relief valve does not open at the set pressure or sticks open, repair or replace a faulty oil pressure relief valve as required. Refer to "26.1.1.1 Verify Repairs" .
   2. If the relief valve is fine, refer to "26.1.1.1 Verify Repairs" .

Section 26.1.1.1
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.