5033638 JOHNSON *BOLT, CAM SHAFT HOUSING

Table 1
CDL Codes and Description Comments
1627-5
Fuel Pump Relay : Current Below Normal The engine Electronic Control Module (ECM) detects an open circuit at the fuel pump relay for 60 seconds.
The ECM detects a short to battery voltage for the fuel pump relay.
The ECM can only detect this condition when the output driver is not activated.
1627-6
Fuel Pump Relay : Current Above Normal The engine ECM detects a short circuit for the fuel pump relay.
The ECM can only detect this condition when the output driver is activated.
4550-5
Electric Fuel Transfer Pump Relay : Current Below Normal This code indicates that there is a problem with the Clean Fuel Module (CFM) fuel priming pump relay and /or electrical circuit.
4550-6
Electric Fuel Transfer Pump Relay : Current Above Normal This code indicates that there is a problem with the Clean Fuel Module (CFM) fuel priming pump relay and /or electrical circuit. The engine may be equipped with a Clean Fuel Module (CFM) which provides extra fuel filtration along with an additional fuel lift pump in order to pull fuel from the fuel tank. If the engine is equipped with the CFM module, the fuel will flow from the fuel tank, to the CFM priming pump, then through the CFM filters. Once the fuel leaves the CFM filters, fuel flows into the engine fuel priming pump, then through the additional filters before flowing into the fuel transfer pump. The fuel is pressurized and flows through the last fuel filter block before entering the high-pressure pump. The fuel sent from the high-pressure pump, to the fuel rail, where fuel then flows through the injectors into the cylinders. Refer to Systems Operation, "Fuel System Operation" for more detail.
Illustration 1 g03745191
Schematic of the low-pressure fuel system (typical configuration) without Clean Fuel Module.
(1) Secondary fuel filters
(2) Tertiary filter
(3) High-pressure fuel system
(4) Pressure regulator
(5) Check valve for the outer wall of the fuel rail
(6) Check valve
(7) Electric fuel priming pump
(8) Mechanical fuel transfer pump
(9) Primary filter/water separator
(10) Fuel tank
Illustration 2 g03745767
Schematic of the low-pressure fuel system (typical configuration) with Clean Fuel Module.
(11) EMP WP29
(12) Fuel Transfer Pump
(13) High Pressure Fuel Pump
(14) Tank
Table 2
Component Electrical Checkout
Engine Fuel Supply Pump Actuator Fuel Pump Relay Command Override
Engine Fuel Filter Circulating Pump (CFM) Electric Fuel Transfer Pump Relay Override
Illustration 3 g03745246
Typical schematic for the fuel priming pump
Table 3
Troubleshooting Test Steps Values Results
1. Determine the Diagnostic Code
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Wait at least 30 seconds in order for the diagnostic codes to become active.
C. Look for an active -5 code or for a logged -6 code
Diagnostic Trouble Codes
Results: There is an active or there is a logged -5 code.
Proceed to Test Step 2.
Results: There is an active or there is a logged -6 code.
Proceed to Test Step 3.
2. Check the Wiring for an Open Circuit
A. Verify that the harness connector is free of debris, free of corrosion and securely connected.
B. Disconnect the solenoid from the engine harness.
C. Connect a jumper wire between the terminals of the harness connector for the suspect coil. The coil is replaced with a short circuit.
D. Perform the appropriate electrical checkout. Refer to Table 2.
Open Circuit
Results: A -5 code became active during the electrical checkout.
The ECM did not detect the jumper wire. There is an open circuit in the wiring between the coil and the ECM connector. There may be a problem with a connector.
Repair: Repair the appropriate harness wiring or replace the appropriate harness.
Verify that the problem is resolved.
Results: A -6 code is activated during the electrical checkout. The ECM detected the jumper wire. There is a problem with the solenoid. Clear the -6 code by cycling the keyswitch to the Off position.
Repair: Replace the solenoid.
Verify that the problem is resolved.
3. Check the Wiring for a Short Circuit
A. Disconnect the solenoid from the engine harness.
B. Clear the -6 code by cycling the keyswitch to the Off position.
C. Perform the appropriate electrical checkout. Refer to Table 2.
Short Circuit
Results: A -6 code became active during the electrical checkout.
The ECM did not detect the open circuit. There is a short circuit in the wiring between the coil and the ECM connector. There may be a problem with a connector.
Repair: Repair the appropriate harness wiring or replace the appropriate harness.
Verify that the problem is resolved.
Results: A -5 code became active during the electrical checkout.
The ECM detected the open circuit. The wiring is OK. The coil has a short circuit.
Repair: Replace the solenoid.
Verify that the problem is resolved.