HOOK AS 3967038 - Caterpillar

Note: The following conditions must exist before any of the above codes will become active:
The ECM has been powered for at least 2 seconds.
There are no active 168-X diagnostic codes.The ECM will log the diagnostic code. If equipped, the warning light will come on.This procedure covers open circuit diagnostic codes and short circuit diagnostic codes that are associated with the following sensors that are connected to the ECM:
Coolant temperature sensor
Intake manifold air temperature sensor
Fuel temperature sensor
Air inlet temperature sensor
Auxiliary temperature sensor (if equipped)
NRS inlet temperature sensorThe following background information is related to this procedure:The troubleshooting procedures for the diagnostic codes of each temperature sensor are identical. The temperature sensors have two terminals. The signal line is connected to each sensor connector terminal 1. Terminal 2 is the return line. The signal voltage from terminal 1 of each sensor is supplied to the appropriate terminal in 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 to detect an open in the signal circuit. When the ECM detects a voltage above a threshold on a signal circuit, an open circuit diagnostic code (XXX-3) is communicated to the engine ECM.If the sensor is disconnected, pull-up voltage at the connector indicates that the wires are not open or shorted to ground. If the sensor is disconnected, the absence of pull-up voltage indicates an open in the signal wire or a short to ground. If the sensor is disconnected and the voltage is different from pull-up voltage, the signal wire is shorted to another wire in the harness.
Illustration 1 g06272953
Schematic for passive engine temperature sensors on the P1 connector
Not all connectors are shown. Refer to the appropriate Electrical Schematic.
Illustration 2 g06114240
Schematic for passive engine temperature sensors on the P2 connector
Illustration 3 g01170313
Typical view of an engine temperature sensor
(1) Signal
(2) Ground
Table 2
Troubleshooting Test Steps Values Results
1. Check for Diagnostic Trouble Codes
A. Connect to the electronic service tool.
B. Turn the keyswitch to the ON position.
C. Access the "Active Diagnostic Code" screen on the electronic service tool.
Wait at least 30 seconds in order for the diagnostic codes to become active.
D. Look for one of the diagnostic codes that are listed in Table 1.
Codes
Result: A -3 diagnostic code is active.
Proceed to Test Step 2.
Result: A -4 diagnostic code is active.
Proceed to Test Step 3.
Result: For a diagnostic code that is logged but not currently active, Proceed to Test Step 4.
2. Create a Short at the Sensor Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the suspect sensor.
C. Install the jumper wire between terminal 1 (sensor signal) and terminal 2 (sensor return) at the sensor connector.
D. Turn the keyswitch to the ON position.
E. Monitor the diagnostic codes on the electronic service tool. Check for an active -4 diagnostic code for the suspect sensor.
Wait at least 30 seconds in order for the diagnostic codes to become active.
F. Turn the keyswitch to the OFF position.
Short Circuit Recognized
Result: The -3 diagnostic code remains active for the suspect sensor.
Repair: There