BOLT 1D4566 - Caterpillar

System Operation Description:Use this procedure to troubleshoot any suspect problems with the marine transmission oil temperature sensor.This procedure covers the following diagnostic codes:
177-03 Transmission Oil Temperature open/short to +batt
177-04 Transmission Oil Temperature short to groundPull-up VoltageThe ECM continuously outputs a pull-up voltage on the circuit for the sensor signal wire. The ECM uses this pull-up voltage in order to detect an open in the signal circuit. When the ECM detects the presence of a voltage that is above a threshold on the signal wire, the ECM will generate a -03 diagnostic code.If the sensor is disconnected at the sensor connector, the presence of pull-up voltage at the sensor connector indicates that the signal wire and the return wire from the sensor connector to the ECM are good.If the sensor is disconnected at the sensor connector, the absence of pull-up voltage at the sensor connector indicates an open in the signal wire, an open in the return wire, or a short to ground.If the sensor is disconnected at the sensor connector and the voltage on the signal wire at the sensor connector is different from pull-up voltage, the signal wire is shorted to another wire in the harness.
Illustration 1 g01134360
Schematic for the marine transmission oil temperature sensorTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01130316
Engine components that are associated with the marine transmission oil temperature sensor (1) J137/P137 connector for the marine transmission oil temperature sensor (2) J2/P2 ECM connectors
Thoroughly inspect connectors (2). Inspect the connectors for the sensor (1). Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01134390
P2 terminals that are associated with the marine transmission oil temperature sensor (P2-17) Return (P2-27) Marine transmission oil temperature (P2-72) +5 VDC
Illustration 4 g01134372
J137 harness connector for the marine transmission oil temperature sensor (A) Supply (B) Return (C) Signal
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the marine transmission oil temperature sensor.
Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from the marine transmission oil temperature sensor to the ECM.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes.Note: Wait at least 15 seconds in order for the diagnostic codes to