SWITCH-ROTARY 1620568 - Caterpillar

System Operation Description:Use this procedure to troubleshoot diagnostic codes for open circuits or short circuits for the circuits of these parameters:
Filtered engine oil pressure
Air inlet pressure
Intake manifold air temperature
Engine oil temperature
Unfiltered engine oil pressure
Fuel quality
Compressor discharge pressureThis procedure covers the following diagnostic codes:
100-3 Engine Oil Pressure Sensor : Voltage Above Normal
100-4 Engine Oil Pressure Sensor : Voltage Below Normal
100-4 Engine Oil Pressure Sensor : Voltage Below Normal
106-3 Air Inlet Pressure Sensor : Voltage Above Normal
106-4 Air Inlet Pressure Sensor : Voltage Below Normal
172-3 Intake Manifold Air Temperature Sensor : Voltage Above Normal
172-4 Intake Manifold Air Temperature Sensor : Voltage Below Normal
175-3 Engine Oil Temperature Sensor : Voltage Above Normal
175-4 Engine Oil Temperature Sensor : Voltage Below Normal
542-3 Engine Oil Pressure Sensor - Before Oil Filter : Voltage Above Normal
542-4 Engine Oil Pressure Sensor - Before Oil Filter : Voltage Below Normal
2449-5 Fuel Quality Sensor : Current Below Normal
2449-6 Fuel Quality Sensor : Current Above Normal
2852-3 Compressor Discharge Pressure Sensor : Voltage Above Normal
2852-4 Compressor Discharge Pressure Sensor : Voltage Below Normal
3185-3Engine Throttle Valve Differential Pressure Sensor : Voltage Above Normal
3185-4Engine Throttle Valve Differential Pressure Sensor : Voltage Below Normal
3185-12Engine Throttle Valve Differential Pressure Sensor : Failure Note: The air inlet pressure sensor may be a PWM sensor or an analog sensor. Determine the type of sensor before you use this procedure. The air inlet pressure sensor is a PWM sensor if a wire is installed in P1-10. Refer to Troubleshooting, "Sensor Signal (PWM) - Test" if the air inlet pressure sensor is a PWM sensor. The air inlet pressure sensor is an analog sensor if a wire is installed in terminal P1-15 or P5-15.A -3 code is probably caused by a problem in an engine harness. There may be an open circuit in a harness, or a short circuit to a positive voltage source in a harness. The next likely cause is a sensor problem. The least likely cause is a problem with a control module.A -4 code is probably caused by a short circuit to ground in an engine harness. The next likely cause is a sensor problem. The least likely cause is a problem with a control module.a -12 code is caused by an issue detected with the throttle valve differential pressure sensor.Logged diagnostic codes provide a historical record. Before you begin this procedure, use Caterpillar Electronic Technician (ET) to print the logged codes to a file.This troubleshooting procedure may generate additional diagnostic codes. Keep your mind on correcting the cause of the original diagnostic code. Clear the diagnostic code after the problem is resolved.
Illustration 1 g01960785
Schematic for the active analog inputs
Test Step 1. Inspect the Electrical Connectors and WiringNote: For the following steps, refer to Troubleshooting, "Electrical Connectors - Inspect".
Remove the electrical power from the engine.
Thoroughly inspect all connectors in the circuit that is suspected of failure.
Check the torque of the allen head screws on the Electronic Control Module (ECM).
If you are troubleshooting a problem with an analog sensor, perform a 45 N (10 lb) pull