DRIVE GP-FAN 4662139 - Caterpillar

Three different types of pressure sensors are found on this engine.The first type of sensor found is commonly seen on other Cat applications which is a 3 wire analog, active pressure sensor.The second type of sensor found is another 3 wire analog, active pressure sensor, 439-4065 Sensor, used for a fuel rail pressure measurement. The wiring to this sensor varies from the typical 3 wire pressure sensors found elsewhere on the engine.
Terminal 1: Sensor Ground
Terminal 2: Sensor Signal
Terminal 3: Sensor Supply VoltageThe third type of sensor found on the engine is a combination pressure and temperature sensor. This sensor is a 4 wire sensor that has a common power supply and ground with two independent signal wires, one for pressure feedback and one for temperature feedback.
Terminal 1 : Sensor Ground
Terminal 2: Temperature Signal
Terminal 3: Sensor Supply Voltage
Terminal 4: Pressure SignalThe supply voltage is routed to terminal 1 of each sensor connector. The sensor return is routed to terminal 2 of each sensor connector. The sensor signal is routed to terminal 3 of each sensor connector. The Electronic Control Module (ECM) provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply.Diagnostics on the Cat® Electronic Technician (ET)Wiggle Test - The Wiggle Test allows you to monitor the status of the signals from the sensors.For additional information regarding the Wiggle Test, refer to the documentation that accompanies the Cat ET software.
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: A -3 code is active.
Proceed to Test Step 2.
Result: A -4 code is active.
Proceed to Test Step 3.
Result: A -20 or 21 code is active or logged
Proceed to Test Step 6.
2. Create a Short at the Sensor Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the sensor with the active -3 code.
C. Install the jumper wire between the following terminals at the sensor connector:
- Terminal 3 (signal) and Terminal 2 (sensor return)
D. Connect Cat ET.
E. Use Cat ET to monitor the following:
-4 code
F. Turn the keyswitch to the OFF position.
Create a Short
Result: A -4 code did not become active.
Proceed to Test Step 4.
Result: A -4 code became active.
Repair: The wiring harness is OK. Replace the sensor.
Verify that the repair eliminated the problem.
3. Create an Open at the Sensor Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the sensor with the active -4 code.
C. Connect Cat ET.
D. Use Cat ET to monitor the following:
-3 code
E. Turn the keyswitch to the OFF position.
Create an Open
Result: A -3 code did not become active.
Proceed to Test Step 4.
Result: A -3 code became active.
Repair: The wiring harness is OK. Replace the sensor.
Verify that the repair eliminated the problem.
4. Check the 5 VDC Supply Voltage at the Sensor Connector
A. Turn the keyswitch to the ON position.
B. Measure the voltage at the sensor connector between the following pins:
Pin 1 and Pin 2
C. Reconnect the sensor.
5.0