BATTERY 4838978 - Caterpillar

Illustration 1 g00884883
Schematic
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P1 ECM connectorTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect J1/P1 ECM connector, J2/P2 ECM connector, J3/P3 customer connector, and all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.Expected Result:All connectors, pins, and sockets should be completely inserted and coupled. The harness and wiring should be free of corrosion, abrasion, and pinch points. All connections and grounds should be tight and free of corrosion.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 2. Check for Shorts in the Harness from the ECM to the Digital Sensors
Disconnect ECM connector J1/P1 and all of the digital sensors.
Measure the resistance between P1:35 (Digital Sensor +8 VDC) and engine ground.
Measure the resistance between P1:35 (Digital Sensor +8 VDC) and P1:30 (Sensor Return).Expected Result:The resistance should be greater than 20,000 Ohms for each measurement.Results:
OK - Proceed to Test Step 3.
Not OK - There is a short between the ECM and the sensor.Repair: Repair the circuit. Stop.Test Step 3. Check for Open Circuits in the Harness Between the ECM and the Digital Sensors
Turn the keyswitch to the OFF/RESET position and install a 7X-1715 Adapter Cable (40-Pin Breakout T) at ECM connector J1/P1.
Use a suitable piece of wire to short P1:35 (Digital Sensor +8 VDC) and P1:30 (Sensor Return) at the breakout.
Disconnect all of the digital sensors.
Measure the resistance between terminal A (+8 VDC) and terminal B (Ground) of the connector for each digital sensor.
Remove the wire short from the breakout.Expected Result:The resistance should be less than 10 Ohms for each measurement.Results:
OK - Proceed to Test Step 4.
Not OK - There is an open circuit in the wiring harness between the sensor and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 4. Check the Digital Sensor Supply Voltage at the Sensor Connectors
Disconnect all of the digital sensors.
Turn the keyswitch to the ON position.
Measure the voltage across terminal A (+8 VDC) and terminal B (Ground) of the connector for each digital sensor.Expected Result:The digital sensor supply voltage should be 8.0 0.5 VDC.Results:
OK - The supply voltage is reaching the sensor. Proceed to Test Step 5.
Not OK - The supply voltage is not reaching the sensor. Proceed to Test Step 7.Test Step 5. Check the Digital Sensor for an Internal Short
Disconnect all of the digital sensors.
Turn the keyswitch to the ON position.
Reconnect one digital sensor at a time while you observe the voltage across P1:35 (Digital Sensor +8 VDC) and P1:30 (Sensor Return) at the breakout.Expected Result:The supply voltage should be 8.0 0.5 VDC. The voltage should not drop when the sensors are connected.Results:
OK - The sensor does not have an internal short.Repair: Refer to Troubleshooting, "Electrical Connectors - Inspect" if the problem is intermittent. Stop.
Not OK - The sensor may have an internal short. Proceed to Test Step 6.Test Step 6. Temporarily Install a New Sensor
Remove the suspect sensor.
Temporarily install a