PLATE-ORIFICE 8P5141 - Caterpillar

System Operation During Engine OperationThe intake valve actuation system does not operate until the engine has reached normal operating temperature. Also, the engine must meet certain operating conditions in order to activate the intake valve actuation system.There are three housings under the valve cover. Each housing contains two actuators. There is a solenoid for each actuator. The ECM sends a command to a solenoid when the ECM requires the intake valves for a cylinder to remain open. The ECM monitors the current flow through the circuit for the solenoid. The ECM activates a diagnostic code if the current flow is below normal or above normal."Intake Valve Actuator Solenoid Test"This test is available on the Caterpillar Electronic Technician (ET). The test helps diagnose problems with the circuits for the solenoids. The following conditions must be met before the test will function:
Engine speed must be zero.
Vehicle speed must be zero.
The transmission gearshift lever must be in neutral.
Illustration 1 g02300033
Schematic for the C15 engine
Illustration 2 g01185728
P2 terminals for the intake valve actuators (18) Actuator 4 return (21) Actuator 5 return (22) Actuator 2 return (31) Actuator 3 return (42) Actuator 6 return (50) Actuator 1 return (58) Actuator 5 & 6 supply (67) Actuator 3 & 4 supply (68) Actuator 1 & 2 supply
Table 2
Troubleshooting Test Steps     Values     Results    
1. Inspect the Electrical Connectors and the Wiring
A. Check the engine harness between the P2 connector and the connectors near the grommets. Look for the following problems:
1. Moisture
2. Loose connectors or damaged connectors
3.Damage that is caused by excessive heat
4. Damage that is caused by chafing
5. Improper routing of wiring
6. Damaged insulation
B.Inspect the connectors near the grommets. The connectors must be clean and dry.
C. Perform a
45 N (10 lb) pull test on each of the wires in the connectors. This test verifies that the wire is properly crimped to the terminal and that the terminal is properly inserted into the connector.
   
Moisture
Damage to connectors    
Result: The wiring is OK.
If you are troubleshooting a -5 code, proceed to Test Step 2.
If you are troubleshooting a -6 code, proceed to Test Step 4.
Result: The wiring is not OK.
Repair the wiring problem. Replace parts, if necessary. Perform the "Intake Valve Actuator Solenoid Test".
If all of the actuators pass the test, troubleshooting is complete. Return the unit to service.
   
2. Short the External Wiring Harness
A.Connect a jumper wire to the engine harness connector. Connect the jumper wire between the appropriate terminals for the supply and for the return of the suspect actuator.
The jumper will replace the actuator and the valve cover wiring harness with a short circuit. Refer to Illustration 1 or Illustration 2.
B. Perform the "Intake Valve Actuator Solenoid Test". Determine the test result for the suspect cylinder.
   
Short Circuit indicated    
Result: The test result indicated "Not Active: Device Open" for the suspect cylinder.
The ECM did not detect the jumper wire. There is an open circuit in the wiring between the valve cover connector and the P2 connector. There may be