RING 5W0965 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the system only when there is an active diagnostic code or when a diagnostic code can easily be activated. This procedure covers diagnostic codes for the following sensors:
Boost pressure sensor
Oil pressure sensor
Barometric pressure sensor
Injection actuation pressure sensorUse this procedure for the following diagnostic codes:
100-3 Engine Oil Pressure voltage high
100-4 Engine Oil Pressure voltage low
102-3 Boost Pressure Sensor voltage high
102-4 Boost Pressure Sensor voltage low
102-7 Boost Pressure not responding
108-3 Barometric Pressure Sensor voltage high
108-4 Barometric Pressure Sensor voltage low
164-3 Injection Actuation Pressure voltage high
164-4 Injection Actuation Pressure voltage lowThe troubleshooting procedures for the diagnostic codes of each pressure sensor are identical. The Engine Control Module (ECM) sends a +5 V supply to terminal A for 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 J2 ECM connector.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 wire, the ECM will generate a -3 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.108-3 Diagnostic Code and High Crankcase PressureSome atmospheric pressure sensors that are located in the engine block actually sense crankcase pressure rather than atmospheric pressure. With this type of installation, crankcase pressure of approximately 14 kPa (2 psi) can cause the 108-3 diagnostic code to be generated.Before you proceed with this test, determine whether the sensor is sensing crankcase pressure or atmospheric pressure.If the sensor is sensing crankcase pressure, connect Caterpillar Electronic Technician (ET) to the ECM and clear the diagnostic code. Do not start the engine. Maintain electrical power to the ECM. Wait at least 30 seconds for generation of the diagnostic code. Slowly wiggle the wiring for the sensor in an attempt to generate an intermittent code.If the 108-3 code is generated, continue with the functional test.If the 108-3 code is not generated, there is either a problem with high crankcase pressure or the code is intermittent, due to a loose connector or damaged wiring.A plugged crankcase breather will cause excessive crankcase pressure. Leakage of the crankshaft seal can occur. Sealing of the piston rings can be lost. This will enable crankcase blowby to