| Diagnostic Codes Table | ||
|---|---|---|
| CDL Code and Description | Conditions which Generate this Code | System Response |
| 18-8 Fuel Control Valve : Abnormal Frequency, Pulse Width, or Period | The controller for the primary fuel control valve has detected an error at the input for the Pulse Width Modulated signal (PWM). The problem is communicated to the Electronic Control Module (ECM) via the CAN data link. | Control for the primary fuel control valve reverts to the CAN data link. |
| 18-9 Fuel Control Valve : Abnormal Update Rate | The engine ECM did not receive the expected data link information from the controller for the primary fuel control valve. | Control for the primary fuel control valve reverts to the PWM signal. |
| 3414-8 Fuel Control Valve #2 : Abnormal Frequency, Pulse Width, or Period | The controller for the secondary fuel control valve has detected an error at the input for the PWM signal. The problem is communicated to the ECM via the CAN data link. | Control for the secondary fuel control valve reverts to the CAN data link. |
| 3414-9 Fuel Control Valve #2 : Abnormal Update Rate | The engine ECM did not receive the expected data link information from the controller for the secondary fuel control valve. | Control for the secondary fuel control valve reverts to the PWM signal. |
This engine is equipped with a high pressure common rail fuel system. The fuel pressure for the high pressure common rail fuel system is generated by the high-pressure fuel pump. Output pressure regulation for the high-pressure fuel pump is provided by the fuel control valve. The fuel control valve is a mechanical valve that is part of the high-pressure fuel pump. The valve regulates the fuel pressure that is produced by the pump by controlling the volume of fuel that enters the pump. The valve is controlled by an electrical actuator. Control for the actuator is provided by an electronic controller that is part of the actuator.
The engine ECM communicates a desired throttle position to the controller for the fuel control in the form of a PWM signal. The PWM signal is generated by a signal driver at the ECM and the signal is sent to the controller for the fuel control valve.
Note: The desired throttle position is also communicated via the CAN data link as a throttle backup control.
The PWM signal that is used for the desired throttle position has a constant frequency of 500 Hz. At low engine idle, the signal will have a duty cycle of approximately 10 percent. At high engine idle with no load on the engine, the signal will have a duty cycle of approximately 20 to 25 percent. At high engine idle with a full load on the engine, the signal will have a duty cycle of approximately 50 to 60 percent.
The desired throttle position can be viewed on Caterpillar Electronic Technician (ET). View the status of the "Fuel Actuator Position Command" parameter in order to determine the desired throttle position of the engine. At low engine idle, the "Fuel Actuator Position Command" will be approximately 10 to 15 percent. At high engine idle with no load on the engine, the "Fuel Actuator Position Command" will be approximately 20 to 25 percent. At high engine idle with a full load on the engine, the "Fuel Actuator Position Command" will be approximately 40 to 50 percent.
A power module is used to supply electrical power to the controller for the fuel control valve. The power module is used to convert battery voltage (24 VDC) to 14.0 ± 1.5 VDC that is used by the controller. The suppression module is circuit protected by the ECM circuit breaker located in the low current power distribution panel.
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| Illustration 1 | g02574400 |
Schematic of the PWM signal (primary throttle control) for the high-pressure fuel pump | |
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| Illustration 2 | g02576378 |
Schematic of the PWM signal (secondary throttle control) for the high-pressure fuel pump | |
Note: For a schematic and troubleshooting information that is related to the throttle backup control and the CAN data link, refer to Troubleshooting, "Data Link - Test".
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| Illustration 3 | g02576597 |
Location of the connectors at the control box that are for the fuel control (typical top front engine view) (1) Right rail connector (2) Secondary fuel harness (3) Control assembly input connector (secondary ECM) (4) Power module for the secondary fuel control valve (5) Control assembly output connector (6) Control assembly input connector (primary ECM) (7) Relay for the secondary keyswitch circuit (8) Relay for the primary keyswitch circuit (9) Power module for the primary fuel control valve (10) Primary power harness (11) J1/P1 connector (primary ECM) (12) J1/P1 connector (primary ECM) (13) Secondary power harness | |
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| Illustration 4 | g02576818 |
Location of the low current power distribution panel (front left side engine view) (14) Primary power harness (15) Secondary power harness (16) Low current power distribution panel (17) High current power distribution panel | |
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| Illustration 5 | g02577199 |
Location of the connections and circuit breakers at low current power distribution panel (16) for the fuel control (18) Hard stop relay (primary) (19) Hard stop relay (secondary) (20) Primary ECM breaker (21) Secondary ECM breaker (22) Secondary keyswitch breaker (23) Primary keyswitch breaker (24) Secondary terminal strip (25) Primary terminal strip | |
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| Illustration 6 | g02578240 |
Location of the connectors at the high-pressure fuel pump (left side high-pressure fuel pump view) (26) Connector for the controller at the fuel control valve (primary) | |
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| Illustration 7 | g02578241 |
Location of the connectors at the high-pressure fuel pump (right side high-pressure fuel pump view) (27) Connector for the controller at the fuel control valve (secondary) | |
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| Illustration 8 | g01318105 |
Terminal locations at the P1 connectors (primary ECM and secondary ECM) (P1-38) PWM signal (P1-70) Keyswitch | |
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| Illustration 9 | g01318358 |
Terminal locations at the connector for the primary power module and secondary power module (Terminal 1) −Battery (Terminal 5) Supply voltage (output) (Terminal 8) Return (output) (Terminal 12) +Battery | |
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| Illustration 10 | g01477832 |
Terminal locations at the right rail connector for the primary fuel control valve (Terminal 16) Supply (Terminal 17) Return (Terminal 48) PWM signal (Terminal 70) Keyswitch | |
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| Illustration 11 | g01318220 |
Terminal locations at the controller for the fuel control valve (primary and secondary) (Terminal 1) Supply (Terminal 5) Return (Terminal 8) Keyswitch (Terminal 11) PWM signal | |
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| Illustration 12 | g01478322 |
Terminal locations at the primary fuel harness connector (Terminal 2) Supply (Terminal 3) Return (Terminal 8) Keyswitch (Terminal 9) PWM signal | |
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| Illustration 13 | g02578838 |
Terminal locations at the secondary fuel harness connector (Terminal 1) Supply (Terminal 5) Return (Terminal 8) Keyswitch (Terminal 11) PWM signal | |
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| Illustration 14 | g01481575 |
Terminal locations at the primary keyswitch relay and the secondary keyswitch relay (Terminal 1) +Battery (Terminal 2) −Battery (Terminal 4) Keyswitch power (Terminal 5) Keyswitch power from the control panel | |
| Troubleshooting Test Steps | Values | Results |
|---|---|---|
1. Check for an Active Diagnostic Code A. Connect Cat ET to the service tool connector. B. Restore the electrical power to the ECM. C. Monitor the diagnostic codes on Cat ET. Check and record any diagnostic codes. Note: Wait at least 30 seconds in order for the diagnostic codes to become active. D. Determine if a diagnostic code has occurred several times. Note: A diagnostic code that is logged several times is an indication of an intermittent problem. Most intermittent problems are the result of a bad connection between a socket and a pin in a connector. An intermittent electrical problem can also exist as a bad connection between a wire and a terminal. E. Look for one or more of the following diagnostic codes that are active or logged: - 18-7 - 18-8 - 18-9 - 18-11 - 18-12 F. Remove the electrical power from the ECM. |
Codes |
Results: No diagnostic codes are active. Repair: There may be an intermittent problem in the harness or in a connector. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct procedures for inspecting electrical connectors. Results: The 18-7 diagnostic code is active. Repair: The actual position and the desired position of the fuel actuator is not within specifications. Replace the fuel control valve. Results: The 18-8 diagnostic code is active. The controller detects a problem in the circuit for the PWM signal from the ECM. Proceed to Test Step 6 Results: The 18-9 diagnostic code is active. The ECM detects a problem with data link communications for the controller. Proceed to Test Step 2 Results: The 18-11 diagnostic code or the 18-12 diagnostic code is active. Repair: During a self test, the controller has detected an internal fault. Replace the fuel control valve. |
2. Check the Supply Voltage at the Controller A. Disconnect the connector at the fuel control valve. B. Restore the electrical power to the ECM. Ensure that the keyswitch is in the ON position. C. Use a multimeter to measure the supply voltage between terminal 1 (supply) and terminal 5 (return) on the harness side of the connector. D. Remove the electrical power from the ECM. |
14.0 ± 1.5 VDC |
Results: The supply voltage is 14.0 ± 1.5 VDC. The correct supply voltage is reaching the controller. Proceed to Test Step 3 Results: The supply voltage is not 14.0 ± 1.5 VDC. The supply voltage is not reaching the controller. Proceed to Test Step 4 |
3. Check for Keyswitch Power at the Controller A. Ensure that the connector for the controller has been disconnected. B. Restore the electrical power to the ECM. Ensure that the disconnect switch is in the ON position. C. Measure the keyswitch power between terminal 8 (keyswitch) at the connector for the controller and the ECM ground strap. D. Remove the electrical power from the ECM. Restore the wiring to the original configuration. |
24.0 ± 1.5 VDC |
Results: The voltage at the keyswitch input is 24.0 ± 1.5 VDC. Repair: The voltage for the keyswitch and the supply are reaching the controller. The controller is being powered, but the controller is not communicating with the ECM. There may be a problem with the wiring for the CAN data link. Repair the CAN data link. Refer to Troubleshooting, "Data Link - Test" for information that is related to troubleshooting the circuit. Results: The voltage at the keyswitch input is not 24.0 ± 1.5 VDC. Repair: The keyswitch power is not reaching the controller. There is a problem in the keyswitch circuit. Repair the circuit. Refer to Troubleshooting, "Electrical Power Supply - Test" for information that is related to troubleshooting the keyswitch circuit. |
4. Check the Supply Voltage (Output) at the Power Module A. Disconnect the connectors for the power module. B. Fabricate two jumper wires that are long enough to create a test circuit at the connector for the power module. Crimp connector sockets to one end of each of the jumper wires. C. Remove the wires from terminal location 5 (supply voltage (output)) and terminal location 8 (return (output)) at the connector for the power module. Install a jumper wire into each of these terminal locations. D. Connect the connectors for the power module. Note: Ensure that the loose ends of the jumper wires are not in contact with any ground source. E. Restore the electrical power to the ECM. F. Measure the supply voltage between the loose ends of the jumper wires at the power module. G. Remove the electrical power from the ECM. Restore the wiring to the original configuration. |
14.0 ± 1.5 VDC |
Results: The supply voltage (output) is 14.0 ± 1.5 VDC. Repair: The supply voltage for the controller is available at the power module, but the supply voltage is not reaching the controller. There is a problem in the harness that is between the power module and the controller for the fuel control valve. Repair the harness or replace the harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details. Results: The supply voltage (output) is not 14.0 ± 1.5 VDC. The power module is not generating the correct voltage. There may be a problem with the battery circuit for the power module. Proceed to Test Step 5 |
5. Check for Battery Voltage to the Power Module A. Disconnect the connectors for the power module. B. Restore the electrical power to the ECM. C. Measure the battery voltage between terminal 12 (+Battery) and terminal 1 (−Battery) on the harness side of the connector for the power module. D. Remove the electrical power from the ECM. Restore the wiring to the original configuration. |
24.0 ± 1.5 VDC |
Results: The battery voltage to the power module is 24.0 ± 1.5 VDC. Repair: The wiring for the power module is OK. The power module is not generating the correct supply voltage for the controller. Replace the power module. Verify that the repair eliminates the original problem. Results: The battery voltage to the power module is not 24.0 ± 1.5 VDC. Repair: There is a problem in the circuit that supplies battery voltage to the power module. Check that the fuse is in good repair. If the fuse is not blown, there is a problem in the harness between the cab of the machine and the power module. Use a multimeter to check the harness wiring in order to locate the problem. Perform the necessary repairs. Verify that the repair eliminates the original problem. |
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| Illustration 15 | g01318220 |
Terminal locations at the connector for the controller (Terminal 1) Supply (Terminal 5) Return (Terminal 8) Keyswitch (Terminal 11) PWM signal | |
| Troubleshooting Test Steps | Values | Results |
|---|---|---|
6. Check the Integrity of the PWM Signal at the Controller for the Fuel Control Valve A. Remove the electrical power from the ECM.: B. Disconnect the harness connector at the controller for the fuel control valve. C. Connect Cat ET to the service tool connector. D. Restore the electrical power to the ECM. Ensure that the keyswitch is in the ON position. E. Use the multimeter to measure the duty cycle and the frequency of the PWM signal. The correct value is approximately 10 percent duty cycle while the keyswitch is in the ON position and the engine is not running. The correct frequency of the signal is 500 Hz. F. Use Cat ET to override the "Fuel Actuator Position Command". Enter a value of 50 percent for the override parameter. Note: Wait at least 30 seconds in order for the override to become active. G. Use the multimeter to measure the duty cycle and the frequency of the PWM signal. The correct value is approximately 50 percent duty cycle with the "Fuel Actuator Position Command" set to a value of 50 percent. The correct frequency of the signal is 500 Hz. H. Use Cat ET to override the "Fuel Actuator Position Command". Enter a value of 100 percent for the override parameter. Note: Wait at least 30 seconds in order for the override to become active. I. Use the multimeter to measure the duty cycle and the frequency of the PWM signal. Note: The correct value is approximately 90 percent duty cycle with the "Fuel Actuator Position Command" set to a value of 100 percent. The correct frequency of the signal is 500 Hz. J. Remove electrical power from the ECM. Restore all of the wiring to the original configuration. |
PWM |
Results: The duty cycle and frequency are correct for all measurements. Repair: The ECM is generating the correct PWM signal and the wiring is OK. There is a problem with the controller. Replace the fuel control valve. Verify that the repair eliminates the original problem. Results: The duty cycle is not consistent with the values that are given as the test results. There is a problem in the circuit for the PWM signal. There may be a problem with the ECM. Proceed to Test Step 7 |
| Troubleshooting Test Steps | Values | Results |
|---|---|---|
7. Check the Integrity of the PWM Signal at the ECM A. Disconnect the J1/P1 ECM connector. B. Use a wire removal tool to remove the wire from terminal location P1-38 (PWM Signal). C. Fabricate a jumper wire that is long enough to create a test circuit at the ECM connector. Crimp a connector socket to the end of the jumper wire. Insert the jumper wire into the terminal location for the PWM signal. D. Connect the J1/P1 ECM connector. E. Carefully insert a black multimeter probe into terminal P1-18 (digital return) at the ECM connector. F. Connect Cat ET to the service tool connector. G. Restore the electrical power to the ECM. Ensure that the keyswitch is in the ON position. H. Use the multimeter to measure the duty cycle and the frequency of the PWM signal between the jumper wire and the multimeter probe. The correct value is approximately 10 percent duty cycle while the keyswitch is in the ON position and the engine is not running. The correct frequency of the signal is 500 Hz. I. Use Cat ET to override the "Fuel Actuator Position Command". Enter a value of 50 percent for the override parameter. Note: Wait at least 30 seconds in order for the override to become active. J. Use the multimeter to measure the duty cycle and the frequency of the PWM signal between the jumper wire and the multimeter probe. The correct value is approximately 50 percent duty cycle with the "Fuel Actuator Position Command" set to a value of 50 percent. The correct frequency of the signal is 500 Hz. K. Use Cat ET to override the "Fuel Actuator Position Command". Enter a value of 100 percent for the override parameter. Note: Wait at least 30 seconds in order for the override to become active. L. Use the multimeter to measure the duty cycle and the frequency of the PWM signal between the jumper wire and the multimeter probe. The correct value is approximately 90 percent duty cycle with the "Fuel Actuator Position Command" set to a value of 100 percent. The correct frequency of the signal is 500 Hz. M. Remove electrical power from the ECM. Restore the wiring to the original configuration. |
PWM |
Results: The duty cycle and frequency are correct for all measurements. Repair: The ECM is generating the correct PWM signal. There is a problem in the harness wiring or in a connector between the ECM and the controller. Repair the harness or replace the harness. Verify that the repair eliminates the original problem. Results: The duty cycle is not consistent with the values that are given as the test results. Repair: The ECM is not generating the correct PWM signal for the controller. The ECM does not appear to be operating properly. Before you consider replacing the ECM, consult the Dealer solutions Network (DSN) for assistance. |