BODY ASSEM. 2S7928 - Caterpillar

System Operation Description:Table 1 lists the diagnostic trouble codes that are covered by this procedure. Also, use this procedure if you have been directed from Troubleshooting, "Symptom Troubleshooting".
Table 1
CDL Code Description Information
1901-5 Engine Intake Valve Actuator #1 : Current Below Normal The ECM monitors the current flow through the circuit for each actuator. If low current flow (open circuit) is detected, a -5 diagnostic code is activated. The ECM continues to try to activate the actuator. If high current flow (short circuit) is detected, a -6 diagnostic trouble code is activated. The ECM will disable the solenoid circuit in order to prevent damage from the high current flow. However, the ECM will periodically try to activate the actuator. If the short circuit remains, this sequence of events will be repeated until the problem is corrected.
The ECM takes the following actions while the code is active:
Engine power is derated by ten percent.
The amber warning lamp is illuminated.
These codes are usually caused by a wiring problem. The wiring problem can be on the outside of the engine or underneath the valve cover.
1901-6 Engine Intake Valve Actuator #1 : Current Above Normal
1902-5 Engine Intake Valve Actuator #2 : Current Below Normal
1902-6 Engine Intake Valve Actuator #2 : Current Above Normal
1903-5 Engine Intake Valve Actuator #3 : Current Below Normal
1903-6 Engine Intake Valve Actuator #3 : Current Above Normal
1904-5 Engine Intake Valve Actuator #4 : Current Below Normal
1904-6 Engine Intake Valve Actuator #4 : Current Above Normal
1905-5 Engine Intake Valve Actuator #5 : Current Below Normal
1905-6 Engine Intake Valve Actuator #5 : Current Above Normal
1906-5 Engine Intake Valve Actuator #6 : Current Below Normal
1906-6 Engine Intake Valve Actuator #6 : Current Above Normal
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