MBE 4000 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 Sensor circuit failed low.‪

Section 27.4.1
Multiple Code Check

Check for multiple codes as follows:‪

1. Turn the ignition ON (key ON, engine OFF).
2. Plug in diagnostic tool and check for multiple codes.
   1. If 175/4 and 3480/4 are present with 100/4, repair the open between pin 82 of the MCM 120–pin connector and the associated sensors. Refer to "27.4.1.1 Verify Repairs" .
   2. If 175/4 is present with 100/4, repair the open between pin 82 of the MCM 120–pin connector and pin 3 of the Engine Oil Temperature/Pressure Sensor. Refer to "27.4.1.1 Verify Repairs" .
3. If only 100/4 is present, refer to "27.4.1 Open Short to Ground Check" .

Section 27.4.2
Open Short to Ground Check

Check for an Engine Oil Temperature/Pressure Sensor open short to ground as follows:‪

1. Disconnect the Engine Oil Temperature/Pressure Sensor.
2. Measure the resistance between pins 1 and 3 of the Engine Oil Temperature/Pressure Sensor.
   1. If the resistance is greater than 130k Ω, replace the Engine Oil Temperature/Pressure Sensor. Refer to "27.4.1.1 Verify Repairs" .
   2. If the resistance is less than 130k Ω, go to step 4 .
3. Measure the resistance between pins 1 and 4 of the combination sensor.
   1. If the resistance is greater than 130k Ω, replace the sensor. Refer to "27.4.1.1 Verify Repairs" .
   2. If the resistance is less than 130k Ω, go to step 4 .
4. Disconnect the MCM 120–pin connector.
5. Measure the resistance between pins 1 and 4 of the sensor harness connector.
   1. If the resistance is greater than 5 Ω, go to step 6 .
   2. If the resistance is less than 5 Ω, repair the short between wires 105 and 54 of the MCM 120–pin connector. Refer to "27.4.1.1 Verify Repairs" .
6. Measure the resistance between pin 4 of the sensor harness connector and ground.
   1. If the resistance is greater than 5 Ω, repair the open between pin 4 of the sensor and pin 54 of the MCM 120–pin connector. See Figure "Engine Oil Temperature/Pressure Sensor" . Refer to "27.4.1.1 Verify Repairs" .
   2. If the resistance is less than 5 Ω, repair the short to ground circuit between pin 54 of the MCM 120–pin connector and ground. See Figure "Engine Oil Temperature/Pressure Sensor" . Refer to "27.4.1.1 Verify Repairs" .

Figure 1. Engine Oil Temperature/Pressure Sensor

Section 27.4.2.1
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.