The Microprocessor Regulated is a generator-set controller. It is used on generator sets from Cummins/Onan, including the 3.3KY, 3.6 KY, 3.6KY and 3.6MKY.
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| 12 | OVERVOLTAGE FAULT—CODE NO. 12 | See an authorized Onan dealer. | |
| 12 | Over Voltage | A. Contact Local Dealer or Distributor | |
| 12 | Overvoltage | ||
| 13 | UNDERVOLTAGE FAULT—CODE NO. 13 | Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. | |
| 13 | Under Voltage | A. Reduce Load Reduce the number of connected appliances, especially air conditioners and battery chargers. (Review load management in Loading the Generator Set.) | |
| 13 | Undervoltage | ||
| 14 | OVERFREQUENCY FAULT—CODE NO. 14 | See an authorized Onan dealer. | |
| 14 | Over Frequency | A. Contact Local Dealer or Distributor | |
| 14 | Overfrequency | ||
| 15 | UNDERFREQUENCY FAULT—CODE NO. 15 | Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. | |
| 15 | Under Frequency | A. Reduce Load Reduce the number of connected appliances, especially air conditioners. | |
| 15 | Underfrequency | ||
| 27 | VOLTAGE SENSE FAULT—CODE NO. 27 | See an authorized Onan dealer. | |
| 27 | Voltage Sense Lost | ||
| 29 | HIGH BATTERY VOLTAGE FAULT—CODE NO. 29 | 1. Check battery bank connections and reconnect if necessary so that the 12 volt batteries serving the genset are connected in parallel (12 v | |
| 29 | High Battery Voltage | ||
| 3 | SERVICE CHECK FAULT—CODE NO. 3 | Check the second-level fault code by pressing STOP once. The second-level fault code will have two-digits. The faults are listed in numerical order in this table. | |
| 3 | Service Check | See second-level fault code. | |
| 3 | Service Check Fault | ||
| 32 | Low Cranking Speed Sense | ||
| 33 | Fault Code 33 | ||
| 35 | Control Card Failure | ||
| 36 | Genset Stopped Without Fault Condition | ||
| 38 | Field Overload (Overvoltage) | ||
| 4 | OVERCRANK FAULT—CODE NO. 4 | 1. Check and fill the fuel tank, as necessary. (Note: The genset fuel pickup is probably higher than the boat engine pickup.) 2. Prime the engine fuel system by holding the control switch at Stop/Prime for 30 seconds. 3. Open any closed fuel valves. 4. Secure the spark plug lead on the spark plug (Page 20). 5. Replace the spark plug (Page 20). 6. Service the air cleaner (Page 19). | |
| 4 | Over Crank | Cranking exceeded 30 seconds without engine starting. | A. Check Fuel Level 1. If fuel level is low, fill the fuel tank. B. Check LPG Level Check and fill the LPG container, as necessary. C. Check Spark Plug(s) 1. Secure the spark plug lead(s) on the spark plug(s). 2. Replace the spark plug(s). D. Check Air Filter Element Replace the air filter if dirty. E. Replace Engine Oil Replace engine oil with oil of proper viscosity for the ambient temperature. F. Check Fuel Fittings 1. Tighten any fuel fitting if there is a fuel or air leak. 2. Reprime the engine fuel system by positioning the control switch to STOP/PRIME for 30 seconds. G. Replace Fuel Filter |
| 4 | Overcrank | ||
| 41 | Generator Rotor Fault | ||
| 42 | Processor Fault | ||
| 45 | Speed Sense Fault | ||
| 48 | Field Sense Fault | ||
| 51 | Processor Failure | ||
| CODE NO. 32 | LOW CRANKING SPEED FAULT—Cranking speed less than 180 rpm for more than 2 seconds | 1. Clean and tighten the positive (+) and negative (−) battery cable connections at the battery and at the genset. 2. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations. 3. Replace engine oil with oil of proper viscosity for ambient temperatures (Page 7). (High oil viscosity can slow down cranking speed.) | |
| CODE NO. 35 | CONTROL CARD FAILURE FAULT—Microprocessor EEPROM error during self-test | See an authorized Onan dealer. | |
| CODE NO. 36 | ENGINE STOPPED FAULT—Engine stopped without command by controller | 1. Check and fill the fuel tank, as necessary. (Note: The genset fuel pickup is probably higher than the boat engine pickup.) 2. Secure the spark plug lead on the spark plug (Page 20). 3. Replace the spark plug (Page 20). 4. Service the air cleaner (Page 19). 5. Check for mechanical damage. | |
| CODE NO. 37 | INVALID GENSET CONFIGURATION FAULT—Genset configuration is preprogrammed at the factory | See an authorized Onan dealer. | |
| CODE NO. 38 | OVERCURRENT FAULT—Low power factor loads | 1. Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners. 2. Have air conditioners and other appliances checked for proper operation. (A locked compressor rotor can cause very low power factor.) | |
| CODE NO. 41 | GENERATOR ROTOR FAULT—Controller unable to sense field or output voltage | See an authorized Onan dealer. | |
| CODE NO. 42 | PROCESSOR FAULT—Microprocessor ROM error during self-test | See an authorized Onan dealer. | |
| CODE NO. 43 | PROCESSOR FAULT—Microprocessor RAM error during self-test | See an authorized Onan dealer. | |
| CODE NO. 45 | SPEED SENSE FAULT—Controller unable to sense quadrature frequency | See an authorized Onan dealer. | |
| CODE NO. 47 | IGNITION FAULT—Controller unable to sense ignition | See an authorized Onan dealer. | |
| CODE NO. 48 | GENERATOR FIELD SENSE FAULT—Controller unable to sense field voltage | See an authorized Onan dealer. | |
| Code 27 | Indicates the control is unable to sense output voltage. | A. Contact Local Dealer or Distributor | |
| Code 29 | Indicates that voltage across the battery system is greater than 19 Volts. | A. Check Battery 1. Check battery bank connections and reconnect if necessary so that the 12 Volt batteries serving the generator set are connected in parallel (12 Volt) rather than in series (24 Volt). 2. Select a lower battery boost charge rate. | |
| Code 32 | Indicates that cranking speed is less than 180 RPM for more than 2 seconds. | A. Check Battery 1. Clean and tighten the positive (+) and negative (–) battery cable connections at the battery and at the generator set. 2. Recharge or replace the battery. Refer to the battery manufacturer's recommendations. B. Replace Engine Oil Replace engine oil with oil of proper viscosity for the ambient temperature. NOTICE: High oil viscosity can slow down cranking speed. | |
| Code 35 | Indicates that a microprocessor EEPROM error occurred during self test. | A. Contact Local Dealer or Distributor | |
| Code 36 | Indicates that the engine stopped without receiving a command from the control. | A. Check Fuel Level 1. If fuel level is low, fill the fuel tank. NOTICE: The generator set fuel pickup tube could be higher up in the fuel tank than the vehicle engine pickup. 2. Prime the engine fuel system by positioning the control switch to STOP/PRIME for 30 seconds. B. Check LPG Level Check and fill the LPG container, as necessary. NOTICE: On cold days, the LPG container may have to be kept at least half full to provide the rate of vaporization necessary to keep up with the generator set fuel demand. C. Check Spark Plug(s) 1. Secure the spark plug lead(s) on the spark plug(s). 2. Replace the spark plug(s). | |
| Code 37 | Indicates that the frequency/RPM ratio is wrong. | A. Contact Local Dealer or Distributor | |
| Code 38 | Indicates low power factor loads. | A. Reduce Load Reduce the number of connected appliances, especially air conditioners and battery chargers. (Review load management in Loading the Generator Set.) B. Check Appliances for Proper Operation Have air conditioners and other appliances checked for proper operation. | |
| Code 41 | Indicates control is unable to sense field or output voltage. | A. Contact Local Dealer or Distributor | |
| Code 42 | Indicates that a microprocessor ROM error occurred during self test. | A. Contact Local Dealer or Distributor | |
| Code 43 | Indicates that a microprocessor RAM error occurred during self test. | A. Contact Local Dealer or Distributor | |
| Code 45 | Indicates the control is unable to sense quadrature frequency. | A. Contact Local Dealer or Distributor | |
| Code 47 | Indicates the control is unable to sense ignition. | A. Contact Local Dealer or Distributor | |
| Code 48 | Indicates the control is unable to sense field voltage. | A. Contact Local Dealer or Distributor | |
| NO. 38 | OVERCURRENT FAULT—CODE NO. 38 (Low power factor loads) | 1. Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners. 2. Have air conditioners and other appliances checked for proper operation. (A locked compressor rotor can cause very low power factor.) | |
| NO. 41 | GENERATOR ROTOR FAULT—CODE NO. 41 (Controller unable to sense field or output voltage) | See an authorized Onan dealer. | |
| NO. 42 | PROCESSOR FAULT—CODE NO. 42 (Microprocessor ROM error during self-test) | See an authorized Onan dealer. | |
| NO. 43 | PROCESSOR FAULT—CODE NO. 43 (Microprocessor RAM error during self-test) | See an authorized Onan dealer. |
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.