CX28 Transmission For Combat and Tactical Vehicles Transmission ; Transfer Case Electronic Control System Caterpillar

Illustration 1	g01253937
Schematic of the bypass pressure switch for the transmission oil filter

This diagnostic trouble code is associated with the bypass pressure switch for the transmission oil filter. The FMI 16 means that the ECU has determined that the oil pressure is above a normal operational range when the engine is running. The code will change to a FMI 3 when the engine is not running. The pressure could cause damage. The bypass switch is a normally open switch. The switch will become closed when the switch is installed. The switch will then become open when the filter is plugged and the oil needs to bypass the filter in order for the transmission to receive oil.

This diagnostic trouble code is active if the following conditions are met:

• Events for engine overspeed are not active.

• The diagnostic trouble code of SPN 168 - FMI 4 for low battery voltage is not active.

• Events for the speeds of the transmission output shaft are not active.

• The transmission oil temperature is above 50 °C (122 °F).

Test Step 1. INSPECT THE HARNESS CONNECTIONS.

1. Turn the disconnect switch to the OFF position.

2. Check the connectors for proper mating.

3. Check the wires at the connector.

4. Check each wire for nicks or signs of abrasion in the insulation.

5. Check for moisture at the connector.

6. Check the connectors for dirty contacts or corroded contacts.

7. Check each pin and each socket of the machine harness connectors.

Expected Result:

The machine harness connectors are tight and free of corrosion.

Results:

• OK - The machine harness connectors are tight and free of corrosion. The oil filter is plugged.

  Repair: Replace the oil filter.

  STOP

• NOT OK - The machine harness connectors are in need of repair.

  Repair: Repair the machine harness or replace the machine harness.

  STOP