CYLINDER HEAD GP 2P6484 - Caterpillar

The Electronic Control Module (ECM) supplies a regulated voltage of 5.0 0.2 VDC to the following sensors:
Engine oil pressure sensor
Atmospheric pressure sensor
Intake manifold pressure sensorThe ECM supplies a regulated voltage of 8.0 0.4 VDC and 5.0 0.2 VDC to the rack position sensor.The supply voltage for the sensors is routed from the ECM to terminal (A) of each sensor connector. The sensor return for the sensors is routed from the ECM to terminal (B) of each sensor connector. The ECM provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply.Note: The sensors are not protected from overvoltage. A short from the supply line to the +Battery may damage the sensors. Repair the sensor supply and check for any active sensor diagnostic codes in order to determine if a sensor has failed.
Illustration 1 g01638014
Illustration 2 g01638357
(10) + 8 VDC (30) + 5 VDC (35) Analog returnTest Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Thoroughly inspect the customer connector J17/P17. Inspect the ECM connector J14/P14. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the coolant level sensor.
Check the allen head screw on the ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The connectors and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or the wiring.Repair: Repair the wiring and connectors or replace the wiring or the connectors. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.Verify that the repair eliminates the problem.STOPTest Step 2. Check Sensor Supply Voltages at the ECM
Reconnect all connectors.
Turn the engine control switch to the ON position.
Measure the voltage betweenP14-30 and P14-35.
Measure the voltage betweenP14-10 and P14-35.Expected Result:The voltage measures 5.0 0.25 VDC between P14-30 and P14-35. The voltage measures 8.0 0.4 VDC between P14-10 and P14-35.Results:
Ok - The voltage measures 5.0 0.25 VDC between P14-30 and P14-35. The voltage measures 8.0 0.4 VDC between P14-10 and P14-35. Proceed to Test Step 3.
NOT OK - The voltage did not measure 5.0 0.25 VDC between P14-30 and P14-35.Repair: Check the supply voltage to the ECM. Refer to Troubleshooting, "Electrical Power Supply - Test". If the voltage is correct, proceed to Test Step 5.
NOT OK - The voltage did not measure 8.0 0.4 VDC between P14-10 and P14-35.Repair: Check the supply voltage to the ECM. Refer to Troubleshooting, "Electrical Power Supply - Test". If the voltage is correct, proceed to Test Step 4.Test Step 3. Check Sensor Supply Voltage at the 5 Volt Sensors
Turn the engine control switch to the ON