The Speed is a generator-set controller. It is used on generator sets from Secure Files - Caterpillar, including the 3456 GENERATOR SET C4G.
| Symptom | Cause | Remedy |
|---|---|---|
| Diagnostic codes 263-03 or 263-04 are logged. | Perform the test procedure to inspect electrical connectors and wiring, check for shorts in the harness from the ECM to the digital sensors, check for open circuits in the wiring harness between the ECM and the digital sensors, and check the digital sensor supply voltage at the sensor connectors. | |
| Duty Cycle - The duty cycle is not correct. | There is a problem in the wiring between P2:31 and the S terminal of the speed control. Verify that the low idle switch is functioning properly. | |
| None of the above diagnostic codes are active or recently logged. | If you are troubleshooting an intermittent problem, refer to Troubleshooting, 'Electrical Connectors - Inspect'. | |
| The ECM is not supplying the correct voltage | Verify your results.Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM. Verify that the repair eliminates the problem. | |
| The ECM is not supplying the correct voltage. | Verify your results.Replace the ECM. Refer to Troubleshooting, 'Replacing the ECM' before replacing the ECM. Verify that the repair eliminates the problem. | |
| The ECS does not have the proper voltage. | Not OK - The ECS does not have the proper voltage. The ECS is suspect. | Repair: Temporarily replace the ECS. If the new ECS eliminates the problem, reinstall the suspect ECS. If the problem returns with the suspect ECS replace the ECS. |
| The droop is not correct. The ECM is not processing the correct signal. | Replace the ECM. Refer to the diagnostic procedure Troubleshooting, 'Replacing the' | |
| The droop on Cat ET does not vary with the turning of the droop adjust potentiometer. | Proceed to Test Step 5. | |
| The duty cycle is not correct. | There is a problem in the wiring between P2:24 and the D terminal of the speed control. | |
| The engine speed/timing sensor is not seated properly or the bracket is bent. The sensor resistance is out of the acceptable range. | Install a new speed/timing sensor: 1. Ensure that the O-ring is installed and free of damage. 2. Ensure that the sensor is properly oriented and that the harness is secured in the proper | |
| The parameter for the emergency stop switch does not display 'OFF'. | Test the ECM by disconnecting relevant connectors and using a jumper wire. Clear any diagnostic codes generated. | |
| The parameter for the emergency stop switch does not display 'ON'. | Deactivate the emergency stop switch, observe the status of the emergency stop switch on Cat ET. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, 'Inspecting Electrical Connectors'. | |
| The parameter on the ECM is incorrect. | Replace the ECM. Refer to the diagnostic procedure Troubleshooting, 'Replacing the ECM'. | |
| The resistance is greater than 10 Ohms. | Repair the switch or wiring and/or replace the switch or wiring. Verify that the repair has eliminated the problem. | |
| The resistance is less than 20,000 Ohms. | Repair the switch or wiring and/or replace the switch or wiring. Verify that the repair has eliminated the problem. | |
| The resistance is not greater than 20,000 Ohms when measuring between P1:35 (Digital sensor +8 VDC) and engine ground or P1:35 (Digital sensor +8 VDC) and P1:29 (Digital return). | Repair the circuit. | |
| The resistance is not less than 10 Ohms when measuring between terminal A (+8 VDC) and terminal B (Digital return) of each digital sensor connector. | Repair the circuit. | |
| The sensor that caused the voltage to drop may have an internal short | The sensor may have an internal short | Temporarily install a new sensor. Observe the voltage across P1:35 (Digital sensor +8 VDC) and P1:29 (Digital return) at the breakout while you connect the new sensor. |
| The supply voltage is not 8.0 + 0.5 VDC when measuring across P1:35 (Digital sensor +8 VDC) and P1:29 (Digital return). | Check the digital sensors for internal shorts. | |
| The supply voltage is not reaching the sensors. | Leave the sensors disconnected. Proceed to Test Step 5. | |
| The suspect sensor was faulty | Permanently install the new sensor. | |
| The symptoms continue when the bypass is installed. | Not OK - The symptoms continue when the bypass is installed. | Repair: The problem is not in the electrical system. There may be a mechanical problem. Refer to the appropriate section in Troubleshooting, 'Troubleshooting Without a Diagnostic Code'. Stop. |
| The throttle position on Cat ET does not vary as the speed adjust potentiometer is adjusted. | The problem may be intermittent. If the problem is intermittent, perform the diagnostic functional test Troubleshooting, 'Inspecting Electrical Connectors'. | |
| The throttle position on the Caterpillar Electronic Technician (ET) does not vary with the turning of the speed adjust potentiometer. | Proceed to Test Step 4. | |
| The voltage does not drop when the sensors are connected | Refer to Troubleshooting, "Electrical Connectors - Inspect" if the problem is intermittent. | |
| The voltage is 5.0 + 0.2 VDC between P1:36 (Analog supply) and P1:30 (Analog return). The voltage is 8.0 + 0.2 VDC between P1:35 (Digital supply) and P1:29 (Digital return). | E Not OK - If the ECM is getting the correct voltage at the +Battery terminal, but the ECM does not supply the correct voltages to the sensors, replace the ECM. Repair: Refer to the diagnostic procedure Troubleshooting, 'Replacing the ECM'. Stop. | |
| There is a short between the ECM and the analog sensors. | Repair the circuit. Verify that the repair eliminates the problem. | |
| There is a short circuit in the harness. | Shorted circuit for the suspect sensor in the wiring harness. | Repair the circuit. Verify that the repair eliminates the problem. |
| There is an open circuit or excessive resistance in the harness or connectors. | Repair the circuit. Verify that the repair eliminates the problem. | |
| Throttle Position - The duty cycle is correct but the throttle position is not correct. The ECM is not processing the correct signal. | Replace the ECM. Refer to the diagnostic procedure Troubleshooting, 'Replacing the ECM'. |
Fault codes and symptom→remedy steps extracted from this controller’s service/owner documentation; verify against the official manual before servicing. Aggregated from the service documentation of generator sets built on this controller.