BOLT-CONNECTING ROD 1P9956 - Caterpillar

System Operation Description:Use this procedure to troubleshoot any suspect problems with the 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 groundThe Electronic Control Module (ECM) supplies 5.0 0.2 VDC to terminal A of each sensor. The sensor common connection is connected to terminal B of each sensor. The signal voltage from terminal C of each sensor is sent to the appropriate terminal on the ECM.Pull-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 circuit, the ECM will generate an open circuit diagnostic code (-03) for the sensor.If the sensor is disconnected at the sensor connector, the presence of pull-up voltage at the sensor connector indicates that the wires from the sensor connector to the ECM are not open or shorted to ground. 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 or a short to ground. If the sensor is disconnected at the sensor connector and the voltage at the sensor connector is different from pull-up voltage, the signal wire is shorted to another wire in the harness.
Illustration 1 g01095363
Schematic for transmission oil temperature sensorTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
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C12 model view (left side engine view) (1) P137 Transmission oil temperature sensor connector (2) J2/P2 ECM connector
Illustration 3 g01153452
3406E, C15, and C18 model view (left side engine view) (1) P137 Transmission oil temperature sensor connector (2) J2/P2 ECM connector
Thoroughly inspect connectors (1) and (2). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
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P2 ECM connector for transmission oil temperature sensor (P2-17) Transmission oil temperature sensor signal (P2-41) Sensor return (P2-42) +5 V sensor supply
Illustration 5 g01094844
Terminals for the temperature sensor
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the allen head screw for each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque value.
Check the harness and wiring for abrasions and for pinch points from the sensor back 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 harness and wiring appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. 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 the Supply Voltage