0502936 JOHNSON CAP, Gas

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Schematic for the engine pressure sensorsTest Step 1. Inspect the Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
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Right side view of the scraper (1) Turbocharger inlet pressure sensor (2) Fuel pressure sensor
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Left side view (3) Injection actuation pressure sensor (4) Boost pressure sensor (5) Atmospheric pressure sensor (6) J2/P2 connectors (7) J1/P1 connectors (8) Engine oil pressure sensor
Thoroughly inspect connectors (6) and (7). Thoroughly inspect the connectors for each engine pressure sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect".
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P2 terminals that are associated with the 5 volt supply for the pressure sensors (P2-17) Return (P2-54) Return (P2-72) +5 VDC (P2-80) +5 VDC
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P1 terminals that are associated with the 5 volt supply for the pressure sensors (P1-2) +5 VDC (P1-3) Return
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Connectors for the sensors (A) Supply (B) Return (C) Signal
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the engine pressure sensors.
Check the torque of the allen head screws for the ECM connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from each sensor back to the ECM.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem in the wiring and/or the connectors.Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the problem is resolved.STOPTest Step 2. Check the Voltage on the +5 V Supply Wire
Turn the keyswitch to the OFF position.
Disconnect the harness connectors for the following sensors:
Injection actuation pressure sensor J204/P204
Boost pressure sensor J200/P200
Atmospheric pressure sensor J203/P203
Fuel pressure sensor J209/P209
Engine oil pressure sensor J201/P201
Turbocharger inlet pressure sensor J205/P205
Turn the keyswitch to the ON position.
Measure the voltage between terminals A (+5 VDC) and B (Return) at each sensor connector on the engine harness.
Turn the keyswitch to the OFF position.
Connect all of the sensors.Expected Result:Each voltage measurement is 5.0 0.2 VDC.Results:
OK - Each voltage measurement is 5.0 0.2 VDC. Proceed to Test Step 3.
Not OK - At least one voltage measurement is not 5.0 0.20 VDC.Repair: Refer to Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test".STOPTest Step 3. Check for Active Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Turn the keyswitch to the ON position.
Observe the "Active Diagnostic" screen on Cat ET. Wait at least 15 seconds so that any codes may become active. Look for an active diagnostic code for an engine pressure sensor.
Determine if the problem is related to a -03 diagnostic code or a -04 diagnostic code.Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active for the engine pressure sensors.Repair: If any of the above codes are logged and the engine is not running properly, refer to Troubleshooting, "Troubleshooting Without a Diagnostic Code".If the engine is running properly at this time, there may be an intermittent problem in a harness that is causing the codes to be logged. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Active -04 code - An -04 diagnostic code is active. Proceed to Test Step 4.
Active -03 code - An -03 diagnostic code is active. Proceed to