5033827 JOHNSON *LEAD, HIGH TENSION

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Schematic for engine pressure sensors
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Locations of the pressure sensors for the C-10 and C-12 engines (typical top and left side engine views) (1) Boost pressure sensor (2) Engine oil pressure sensor (3) Atmospheric pressure sensor (4) Engine Control Module (ECM) (5) P2/J2 ECM connectors
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Locations of the pressure sensors for the C-15 engines (typical left side engine view) (1) Boost pressure sensor (2) Engine oil pressure sensor (3) Atmospheric pressure sensor (4) Engine Control Module (ECM) (5) P2/J2 ECM connectors
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Terminal locations at the P2 ECM connector for the engine pressure sensors (P2-2) Sensor supply (P2-3) Sensor return (P2-14) Atmospheric pressure (P2-24) Engine oil pressure (P2-40) Boost pressure
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Terminal locations at the sensor connector for the engine pressure sensors (Terminal A) Sensor supply (Terminal B) Sensor return (Terminal C) Sensor signalTest Step 1. Determine if the Code is Logged or Active
Connect Cat ET to the service tool connector.
Restore electrical power to the engine ECM.
Monitor the active diagnostic code and the logged diagnostic codes on Cat ET.Note: Wait at least 30 seconds in order for diagnostic codes to become active.Identify the diagnostic code.Results:
Logged code - Repair: Do not troubleshoot a logged code unless the code relates to an operator complaint. If the code is logged and the code does not relate to an operator complaint, clear the code. If the code is logged and the code relates to an operator complaint, proceed to Test Step 2.
Active code - Proceed to Test Step 3.Test Step 2. Check the Integrity of the Connections at the Connectors
Turn the keyswitch to the ON position. Do not start the engine.
Install a 7X-1708 Multimeter Probe (RED) and a 7X-1709 Multimeter Probe (BLACK) onto the test leads of a multimeter.
Check for an intermittent problem at the connector for the suspect sensor:Note: Do not disconnect any harness connectors in order to perform this procedure.
Carefully install the spoons (multimeter probes) into the terminal locations for the +5 volt sensor supply and the sensor return at the connector for the suspect sensor.
While you observe the voltage reading on the multimeter, wiggle the wires and pull on the wires at the connector for the suspect sensor.The voltage reading will not vary more than 0.5 volts for a solid electrical connection.
Remove the spoons (multimeter probes) from the connector.
Check for an intermittent problem at the ECM connector:Note: Do not disconnect any harness connectors in order to perform this procedure.
Carefully install the spoons (multimeter probes) into the terminal locations for the +5 volt sensor supply and the sensor return at the P2 ECM connector.
While you observe the voltage reading on the multimeter, wiggle the wires and pull on the wires for the +5 volt sensor supply and the sensor return at the ECM connector.The voltage reading will not vary more than 0.5 volts for a solid electrical connection.
Remove the spoons (multimeter probes) from the connector.
Turn the keyswitch to the OFF position.Expected Result:The voltage reading did not vary more than 0.5 volts during either test.Results:
OK - The voltage reading did not vary more than 0.5 volts.Repair: The connections are OK at the connectors. There does not appear to be an intermittent problem in the circuit at this time. Return the engine to service.STOP
Not OK - The voltage reading varied more tha