5031776 JOHNSON **KEY (20)

Table 1
Diagnostic Trouble Codes
J1939 Code CDL Code Code Description Comments
1347-5 1779-5 Fuel Rail #1 Pressure Valve Solenoid : Current Below Normal The Engine ECM detects a low current flow in the circuit for the solenoid driver.
The code is logged.
1347-6 1779-6 Fuel Rail #1 Pressure Valve Solenoid : Current Above Normal The Engine ECM detects a high current flow in the circuit for the solenoid driver.
The code is logged.
1348-5 1780-5 Fuel Rail #2 Pressure Valve Solenoid : Current Below Normal The Engine ECM detects a low current flow in the circuit for the solenoid driver.
The code is logged.
1348-6 1780-6 Fuel Rail #2 Pressure Valve Solenoid : Current Above Normal The Engine ECM detects a high current flow in the circuit for the solenoid driver.
The code is logged. Note: The automatic cylinder cutout test is disabled while any of these codes are active.Automatic Configuration of the Solenoid DriversThe connectors for the solenoids are interchangeable. The ECM determines the connector that is connected to each solenoid during each engine start cycle. For this reason, either pump solenoid can be driven by either ECM driver.
Illustration 1 g03343251
Illustration 2 g01959043
Typical left side view
Illustration 3 g01959046
Harness connectors for the solenoids
Illustration 4 g01959049
(P2-50) Solenoid return
(P2-68) Solenoid driver
(P2-77) Solenoid driver
(P2-111) Solenoid return
Table 2
Troubleshooting Test Steps Values Results
1. Determine the Diagnostic Code
A. Establish communication between Caterpillar Electronic Technician (ET) and the applicable Electronic Control Module (ECM) . Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Download the "Warranty Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes.
C. Look for an active or logged -5 code or -6 code.
Diagnostic Trouble Codes
Result: There is an active or there is a logged -5 code
Proceed to Test Step 2.
Result: There is an active or there is a logged -6 code.
Proceed to Test Step 3.
Illustration 5 g03343300
Table 3
Troubleshooting Test Steps Values Results
2. Check the Wiring for an Open Circuit
A. Turn the keyswitch to the OFF position.
B. Verify that the harness connector is free of debris, free of corrosion and securely connected.
C. Disconnect both solenoids from the harness.
D. Connect a jumper wire between terminals 1 and 2 of the harness connector for each coil. Each coil is replaced with a short circuit.
E. Turn the keyswitch to the ON position. Do not start the engine.
F. Connect to Cat ET. Select the Diagnostics tab and perform the "Fuel Rail Pump Solenoid Test".
Short circuit
Result: The test results indicate "Not OK (*Open)" for one or both solenoids.
There is an open circuit in the wiring between a solenoid and the Engine Electronic Control Module (ECM) connector. Check both solenoid wiring circuits. There may be a problem with a connector.
Repair the connectors and/or the wiring. Replace parts, if necessary. Verify that the original problem is resolved.
Perform the "Fuel Rail Pump Solenoid Test" again to verify that the problem is resolved.
Result: The test results indicate "Not OK (*Short)" for both solenoids.
The Engine Electronic Control Module (ECM) detected the jumper wires. There is a problem with a solenoid.
Replace the pump.
Perform the "Fuel Rail Pump Solenoid Test" again to verify that the problem is resolved.
Illustration 6 g03343302
Table 4
Troubleshooting Test Steps Values Results
3. Check the Wiring for a Short Circuit
A.. Verify that the harness connector is free of debris, free of corrosion and securely connected.
B. Connect to Cat ET, Select the Diagnostics tab, and perform the "Fuel Rail Pump Solenoid Test"
C. Record the driver which has the "Not OK (*Short)" result.
D. Remove the driver return wire from the ECM connector that has the "Not OK (*Short)" result.
E. Disconnect the solenoid from the driver circuit that