0390983 JOHNSON PISTON, .030 o.s.

Illustration 1 g01162020
Schematic
Illustration 2 g01162303
P1 ECM connector
(P1-4) +8 V digital supply
(P1-5) Digital return
Illustration 3 g01162233
P2 ECM connector
(P2-56) +8 V digital supply
Illustration 4 g01094844
Sensor connector
Test Step 1. Inspect Electrical Connectors and Wiring
Turn the engine control to the OFF/RESET mode.
Turn the battery disconnect switch to the OFF position.
Thoroughly inspect the J1/P1 and J1/P1 ECM connectors. Thoroughly inspect all connectors that are related to the circuit. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Check the harness and wiring for abrasions and for pinch points from the sensors back to the ECM. Expected Result:All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points. All connections and grounds are tight and free of corrosion.Results:
OK - The harness and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the engine control to the STOP mode.
Turn the battery disconnect switch to the ON position.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Note: Wait at least 15 seconds in order for the diagnostic codes to become active.Expected Result:One of the following diagnostic codes is active:
263-03
263-04 Results:
OK - A 263-03 diagnostic code is active. Proceed to Test Step 3.
OK - A 263-04 diagnostic code is active. Proceed to Test Step 4.
Not OK - No diagnostic code for the digital supply is active. A problem is suspected with a sensor output signal. In order to verify that the sensor is receiving the correct supply voltage, proceed to Test Step 3.Test Step 3. Check the Voltage on the +8 V Supply Wire
Turn the engine control to the OFF/RESET mode.
Turn the battery disconnect switch to the OFF position.
Disconnect all of the digital sensors at the sensor connectors.
Turn the engine control to the STOP mode.
Turn the battery disconnect switch to the ON position.
Measure the voltage between terminal A and terminal B at each of the sensor connectors. Expected Result:The voltage is 8.0 0.4 VDC.Results:
OK - The voltage is 8.0 0.4 VDC. The voltage is correct.Repair: Replace all wires to the original configuration. Clear all diagnostic codes. Check for active diagnostic codes. If the problem is intermittent, refer to Troubleshooting, "Inspecting Electrical Connectors".STOP
Not OK - The voltage is not 8.0 0.4 VDC at one of the sensor connectors. Proceed to Test Step 5.Test Step 4. Disconnect the +8 V Sensor while you Monitor the Active Diagnostic Codes
Turn the engine control to the STOP mode.
Turn the battery disconnect switch to the ON position.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Note: Wait at least 15 seconds in order for the diagnostic codes to become active.
Disconnect the digital sensors one at a time while you monitor Cat ET.
Wait for 15 seconds after the sensor is disconnected. Check for an active diagnostic code on Cat ET. Expected Result:The 263-04 diagnostic code deactivates when a particular sensor is disconnected.Results:
OK - The 263-04 diagnostic code deactivates after disconnecting the suspect sensor.Repair: Reconnect the sensor. If the problem returns after the reconnection of the sensor, disconnect the sensor. If the problem disappears after the disconnection of the sensor, replace the sensor. Reconnect all wires to the original configuration. Clear all diagnostic codes. Verify that the repair eliminates the problem.STOP
Not OK - The 263-04 diagnostic code stays active. Leave the sensor(s) disconnected. Proceed to Test Step 5.Test Step 5. Check the +8 V Supply Wire for a Short to Engine Ground or a Short to another Wire in the Harness
Turn the engine control to the OFF/RESET mode.
Turn the battery disconnect switch to the OFF position.
Disconnect the J1/P1 and J2/P2 ECM connectors.
Leave the digital sensor(s) disconnected at the sensor connectors. Note: Wiggle the harness during the following measurements in order to reveal any intermittent short condition.
Measure the resistance between P1-4 (+8 V digital supply) and every terminal on ECM connector P1 and ECM connector P2.
Measure the resistance between P1-4 (+8 V digital supply) and engine ground.
Measure the resistance between P2-56 (+8 V digital supply) and engine ground. Expected Result:The resistance is more than 20,000 Ohms.Results:
OK - The resistance is more than 20,000 Ohms. The resistance measurement does not indicate a short in the engine harness or a short to engine ground. Proceed to Test Step 6.
Not OK - A resistance measurement is less than 20,000 Ohms. The +8 V digital supply wire is shorted in the engine harness or the +8 V digital supply wire is shorted to engine ground.Repair: Repair the wire or replace the wire. Clear all logged diagnostic codes. Replace all wires to the original configuration. Verify that the repair eliminates the problem.STOPTest Step 6. Check the +8 V Supply and the Sensor Return for an Open Circuit
Install a wire jumper between pin P1-4 (+8 V digital supply) and pin P1-5 (digital return).
Install a wire jumper between pin P2-56 (+8 V digital supply) and pin P1-5 (digital return). Note: Wiggle the harness during the following measurements in order to reveal any intermittent short condition.
Measure the resistance between terminal A and terminal B on each sensor connector.
Remove the wire jumpers. Expected Result:The resistance is less than 5 Ohms.Results:
OK - The resistance is less than 5 Ohms. The resistance measurements do not indicate an open circuit in the engine harness. Proceed to Test Step 7.
Not OK - A resistance measurement is greater than 5 Ohms. The +8 V digital supply wire or the