MBE 900 DDEC VI Troubleshooting – Section 27.4 SPN 100/FMI 4

Section 27.4
SPN 100/FMI 4

A typical diagnosis is an Engine Oil Pressure Switch/Sensor open short to ground.‪

Section 27.4.1
Open Short to Ground Check

Check as follows:‪

1. Disconnect the Engine Oil Pressure Switch/Sensor/Sensor. See Figure "Engine Oil Pressure Switch/Sensor" .
   

   Figure 1. Engine Oil Pressure Switch/Sensor

2. Disconnect the 120–pin MCM connector.
3. Measure the resistance between pins 1 and 2 of the Engine Oil Pressure Switch/Sensor.
   1. If the resistance is greater than 5Ω, go to step 4 .
   2. If the resistance is less than 5Ω, repair the short between wires 54 and 55 of the 120–pin MCM connector. Refer to "27.4.1.1 Verify Repairs" .
4. Measure the resistance between pins 1 of the Engine Oil Pressure Switch/Sensor harness connector and ground.
   1. If the resistance is greater than 5Ω, go to step 5 .
   2. If the resistance is less than 5Ω, repair the short circuit between pin 1 of the Engine Oil Pressure Switch/Sensor harness connector and chassis ground. Refer to "27.4.1.1 Verify Repairs" .
5. Measure the resistance between pin 2 of the Engine Oil Pressure Switch/Sensor harness connector and ground.
   1. If the resistance is greater than 5 Ω, replace the switch. Refer to "27.4.1.1 Verify Repairs" .
   2. If the resistance is less than 5 Ω, repair the short between pin 2 of the Engine Oil Pressure Switch/Sensor harness connector and ground. Refer to "27.4.1.1 Verify Repairs" .

Section 27.4.1.1
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.