MANIFOLD-EXHAUST 7W9621 - Caterpillar

Illustration 1 g03098776
Schematic of the Overload Pressure SensorThis diagnostic code is recorded when the Hydraulic Pump ECM reads the sensor signal voltage and the voltage is too high. The possible causes of this diagnostic code are listed below:
The sensor has failed.
The sensor supply or the ground circuit in the machine harness is open.
The signal circuit in the machine harness is shorted to the +battery.
The signal circuit in the machine harness is open or the sensor is disconnected.
The Hydraulic Pump ECM has failed. This is unlikely.This diagnostic code causes the overload pressure to be shown as the maximum value or the overload pressure intermittently indicates the maximum pressure.Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, that all connections are secure and that all connections are in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure. Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected.Test Step 1. CHECK THE CONTROL AND THE HARNESS.
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the machine harness from the boom overload pressure sensor.
At the machine harness connector for the sensor, measure the voltage (DCV) between the signal contact C (wire H446-PK) and the ground contact B (wire 235-BK).Expected Result:The voltage is 12.0 0.5 DCV. Results:
OK - The voltage is 12.0 0.5 DCV. Repair: The Hydraulic Pump ECM and the machine harness are correct. The sensor has failed. Replace the sensor. STOP
NOT OK - The voltage is NOT 12.0 0.5 DCV.Repair: The Hydraulic Pump ECM or the machine harness has failed. Proceed to Test Step 2.Test Step 2. CHECK THE GROUND CIRCUIT OF THE HARNESS
The sensor remains disconnected from the machine harness.
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the J1 and J2 machine harness connectors from the Hydraulic Pump ECM.
At the machine harness connector for the sensor, measure the resistance between ground contact B (wire 235-BK) and frame ground. Expected Result:The resistance is less than 5.0 ohms.Results:
OK - The resistance is less than 5.0 ohms. The harness resistance is correct. Proceed to Test Step 3.
NOT OK - The resistance