TUBE AS 2436468 - Caterpillar

FMI F02
This fault is recorded when ESTC II reads the signals of the transmission gear switch (rear gear) (wires 738-BR, 739-WH, 740-0R, 741-YL, 742-GN, and 916-BU) as not valid (incorrect). The result of this fault condition is that the transmission does not shift or hunts.The possible causes of this fault are:
Wires 308-YL, 738-BR, 739-WH, 740-0R, 741- YL, 742-GN, or 916-BU are open or shorted to ground between ESTC II and the transmission gear switch.
Wire 202-BK is open between the transmission gear switch and frame ground.
Transmission gear switch has failed.
ESTC II has failed.Note: This procedure uses the shift status mode to check the circuits of the transmission gear switch in the machine harness. For more information, see the topic Mode 2 - Shift Status Mode in the Systems Operation section. It is beneficial for an additional service person to help perform this procedure.Note: An earlier switch exists that is strictly mechanical. The mechanical switch uses the same logic as the current hall effect type switch. However, the mechanical switch opens and closes the circuits to ground through internal diodes. Step 1 of this procedure does not apply to the earlier mechanical switch. For the earlier mechanical switch, start troubleshooting at Step 2.STEP 1. CHECK POWER SUPPLY- The switch must be receiving battery voltage at connector contact 4 (wire 308-YL). At the transmission, remove the cover to expose the transmission gear switch. Remove the two bolts that fasten the switch to the transmission control housing. Disconnect the machine harness from the transmission gear switch. Turn the key start switch to the ON position. At the machine harness connector for the transmission switch, measure the voltage from contact 4 to frame ground.
Voltage is approximately battery voltage. Voltage is correct. Go to Step 2.
Voltage is less than battery voltage. Harness is open or shorted. Check wire 308-YL in the machine harness for an open or a short circuit. Repair or replace the machine harness.STEP 2. CHECK HARNESS - The transmission gear switch remains disconnected from the machine harness as in Step 1. Put the display in Mode 2 (shift status mode). Observe the right digit of the display. Under these conditions, all segments of the right digit must be OFF.
All segments are OFF. The transmission gear circuits in the machine harness are correct (open). Go to Step 4.
All segments are NOT OFF. The segments that are ON correspond to transmission gear circuits in the machine harness that are shorted to ground. Go to Step 3.STEP 3. CHECK FOR SHORT TO GROUND- The transmission gear switch remains disconnected from the machine harness. Turn the disconnect switch to the OFF position. Disconnect the machine harness from ESTC II. Determine the contacts of the machine harness connector that correspond to the segments that were ON in Step 2. See the topic Mode 2 - Shift Status Mode in the Systems Operation section. At the machine harness connector for ESTC II, measure the resistance between the suspected contact and frame ground.
Resistance is less than 5000 Ω.