16701-ZW5-003 Honda CASE, PUMP (Honda Code 8425621).

Table 1
J1939 Code and Description Comments
633-8
Engine Fuel Actuator 1 Control Command : Abnormal Frequency, Pulse Width, or Period The ECM has been notified by the fuel metering valve that the PWM circuit is outside the acceptable range or erratic.
The code is logged.
633-13
Engine Fuel Actuator 1 Control Command : Out of Calibration The fuel metering valve is unable to determine a valid calibration value.
The code is logged.
5418-7
Engine Fuel Actuator #1 : Not Responding Properly The ECM has been notified by the fuel metering valve that the valve is not able to reach the commanded valve position.
5418-11
Engine Fuel Actuator #1 : Other Failure Mode The ECM has been notified by the fuel metering valve that an internal failure has occurred.
5418-12
Engine Fuel Actuator #1 : Failure The ECM has been notified by the fuel metering valve that an internal failure has occurred. The fuel metering valve is an electronic gas valve that controls the flow of fuel to the engine. The fuel metering valve works with the engine ECM to ensure the correct flow of gas in all conditions of engine operation.The ECM sends the desired fuel flow and specific gravity of the gas to the fuel metering valve. The fuel metering valve converts the command signal and the information into a valve position that directly corresponds to the desired gas flow. The position of the fuel metering valve is compensated by these additional factors that are internal to the valve:
A signal for absolute fuel pressure
Differential pressure across the valve
Fuel temperature sensorsThe ECM and the fuel metering valve communicate via the CAN data link. The ECM sends a command signal to the fuel metering valve. The fuel metering valve sends the following information to the ECM: desired valve position, actual valve position, and internal fault diagnosis.If the ECM cannot communicate with the fuel metering valve, the ECM activates a 1442-9 diagnostic code. The problem may be with the power supply to the fuel metering valve. This code may be generated for an intermittent problem. After checking the power circuit for the fuel metering valve, refer to Troubleshooting, "CAN Data Link - Test" for information that is related to troubleshooting the data link circuitry.Self-diagnostic FunctionIf an internal fault is detected by the fuel metering valve, the condition is communicated via the CAN data link. The ECM activates a 5418-12 diagnostic code. The most likely cause of a 5418-12 diagnostic code is an electrical problem or a mechanical problem within the fuel metering valve.For a logged 5418-7 or 5418-11, ensure that the ambient temperature around the actuator and valve assembly is above −40° C (−40° F). If the engine is being operated in colder ambient temperatures, take the appropriate measures that will increase the ambient temperature around the engine. If the ambient temperature is OK, cycle the power to the engine. Place the engine control switch in the "STOP" position. Allow sufficient time for the actuator to calibrate. If one of these codes becomes active during the calibration attempt, there may be a mechanical problem with the valve mechanism. Remove the valve mechanism from the engine. Check for dirt, debris, and blockage in the piping for the fuel system. Replace the fuel metering valve as necessary.CommunicationsThe ECM sends the following information to the fuel metering valve via the CAN data link:
The specific gravity of the fuel
PWM signal for desired fuel flowThe fuel metering valve sends the following information to the ECM via the CAN data link:
Position of the fuel valve
Absolute fuel pressure
Differential pressure across the valve
Fuel temperatureIf the ECM and the fuel metering valve cannot communicate via the CAN data link, a 5418-9 diagnostic code is activated. If the engine is running, the fuel metering valve will use the command signal from the PWM signal. The engine will continue to run. However, if the engine is not running and a 5418-9 diagnostic code becomes active, the ECM will not allow the engine to start.PWM SignalThe ECM sends the command signal for the fuel flow via a PWM signal. If the PWM signal for the flow of fuel is interrupted, a 633-8 diagnostic code will be activated. The fuel metering valve will use the command signal for the fuel flow via the CAN data link.
Illustration 1 g06494901
For the complete circuit details, refer to the full schematic.
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect the Cat® Electronic Technician (Cat ET) Service Tool to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: A -7 code, -11 code, or -12 code active.
Repair: Replace the fuel metering valve.
Result: A -8 code is active.
Proceed to Test Step 2.
Result: A -13 code is active.
Proceed to Test Step 5.
2. Check the Wiring Harness for an Open Circuit
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the L-C1 and L-C2 wiring harness connector from the Electronic Control Module (ECM).
C. Disconnect the fuel metering valve connector.
D. Measure the resistance between the following locations:
- Terminal K (PWM +) of the fuel metering valve connector and terminal 1 of the L-C2 ECM connector
- Terminal L (PWM -) of the fuel metering valve connector and terminal 63 of the L-C1 ECM connector.
Open Circuit
Result: Both