The Digital Electronic Governing is a generator-set controller. It is used on generator sets from Cummins/Onan, including the MDKB.
| Code | Meaning | Cause | Remedy |
|---|---|---|---|
| 1 | HIGH ENGINE TEMPERATURE | 1. Add coolant as necessary and repair leaks (Page 18). 2. Replace the engine thermostat, which might not be opening fully (Page 21). 3. Clean the raw water tubes in the heat exchanger, which might be clogged with scale (Page 22). 4. Flush the coolant system to remove coolant passage fouling (Page 18). | |
| 1 | High Engine Temperature | Coolant level; Grounded or shorted sender lead; Temperature sender resistance; Coolant temperature | Check: Coolant level; Grounded or shorted sender lead; Temperature sender resistance; Coolant temperature |
| 1 | High Engine Temperature — Engine coolant temperature exceeds design limit | Check for and clean a blocked sea water strainer. If above the water line, fill the strainer with water to assist priming; check engine coolant level and add coolant as necessary; check for kinked or leaking hoses and reconnect, reroute or replace; check the V-belt that drives the coolant pump and service as necessary (p. 4-13); inspect the siphon break for proper operation (p. 4-8); check for a worn raw water impeller and replace as necessary (p. 4-12); clean the heat exchanger (p. 4-8); check the bottom of the hull for any blockage at the through-hull fitting; replace the coolant thermostat, which might not be opening fully (p. 4-14); drain and clean the coolant system to remove coolant passage fouling (Page 4-7) | |
| 1 | High engine temperature — Engine coolant temperature exceed design limit | Open the sea valve; Check for and clean a blocked sea water strainer. If above the water line, fill the strainer with water to assist priming; Check engine coolant level, add coolant as necessary and check for and repair leaks (p. 4-7); Check for and reconnect or replace any disconnected, kinked or leaking raw water hoses; Check the bottom of the hull for any blockage at the through-hull fitting; Drain and clean the cooling system to remove fouling (p. 4-7); Replace the coolant thermostat, which might not be opening fully (p. 4-10) | |
| 1 | High engine temperature — First-level shutdown—Engine coolant temperature exceed design limit | Engine coolant temperature exceed design limit | Add coolant as necessary and repair leaks (Page 3-7); Replace the engine thermostat, which might not be opening fully (Page 3-10); Clean the raw water tubes in the heat exchanger, which might be clogged with scale (Page 3-11); Flush the coolant system to remove coolant passage fouling (Page 3-7); Test coolant sender E2 (Page 4-5) and replace if necessary |
| 1 or 2 digit code | Status light on the generator will repeatedly blink a 1 or 2 digit code after a protective shutdown | ||
| 12 | High AC Voltage — After voltage regulation was enabled Output Voltage jumped to more than 125% of rated for 75 milliseconds or to more than 115% of rated for 3 seconds | Check for a tripped generator set circuit breaker, reset if necessary, and run with fewer loads. (A breaker tripping under load can cause generator set voltage to overshoot.); check all fuel fittings and filters for fuel and air leaks and tighten as necessary. (Air bubbles can disrupt generator set frequency/voltage.); prime the engine fuel system for at least 30 seconds (p. 3-3) | |
| 12 | High AC voltage — After voltage regulation was enabled Output Voltage jumped to more than 125% of rated for 75 milliseconds or to more than 115% of rated for 3 seconds | After voltage regulation was enabled Output Voltage jumped to more than 125% of rated for 75 milliseconds or to more than 115% of rated for 3 seconds | See an authorized Onan service representative |
| 12 | High AC voltage — After voltage regulation was enabled Output Voltage jumped to more than 125percent of rated for 75 milliseconds or to more than 115percent of rated for 3 seconds | Push the generator set line circuit breaker OFF, start the generator set. If output voltage is normal, the problem is in the circuits external to the generator set; Check all fuel filters and fittings for fuel and air leaks, tighten as necessary and reprime. (Air bubbles can disrupt frequency.) | |
| 12 | OVERVOLTAGE | See an authorized Onan dealer. | |
| 12 | Overvoltage | Output voltage; Loads; Fuel supply; Sense lead connections; Control plugs fully seated; Sense leads fully seated in connector to control | Check: Output voltage; Loads; Fuel supply; Sense lead connections; Control plugs fully seated; Sense leads fully seated in connector to control |
| 12 | Overvoltage — Controller unable to maintain rated voltage | Controller unable to maintain rated voltage | Push line circuit breaker (Page 2-2) to OFF, start the genset and measure output voltage. If output voltage is normal, the problem is not the genset. If output voltage is high, test and service the generator (Page 5-2) as necessary; Replace controller A1 (Page 4-1) |
| 13 | Low AC Voltage — After voltage regulation was enabled Output Voltage fell to less than 90% of rated for 5 seconds | Push the generator set line circuit breaker OFF and disconnect the PTO, if so equipped. If the generator set now runs and voltage and frequency are normal, reduce the number of electrical and mechanical (PTO) loads; check the fuel tank and fill as necessary. (Note: The arrangement of pickup tubes in the fuel supply tank probably is such that the generator set will run out of fuel before the propulsion engines.); check all fuel fittings and filters for fuel and air leaks and tighten as necessary. (Air bubbles can disrupt generator set frequency/voltage.); replace fuel filters (p. 4-6) | |
| 13 | Low AC voltage — After voltage regulation was enabled Output Voltage fell to less than 90% of rated for 5 seconds | After voltage regulation was enabled Output Voltage fell to less than 90% of rated for 5 seconds | Push the genset line circuit breaker OFF. If the genset now runs, reduce the number of loads |
| 13 | Low AC voltage — After voltage regulation was enabled Output Voltage fell to less than 90percent of rated for 5 seconds | Push the generator set line circuit breaker OFF. If the generator set now runs and voltage and frequency are normal, reduce the number of electrical loads; Check the fuel tank and fill as necessary. (Note: The arrangement of pickup tubes in the fuel supply tank probably is such that the generator set will run out of fuel before the propulsion engines.); Remove combustion air or exhaust system blockages; Prime the engine fuel system for at least 30 seconds (p. 3-3); Check all fuel filters and fittings for fuel and air leaks, tighten as necessary and reprime. (Air bubbles can disrupt frequency.); Replace the fuel filters and reprime (p. 4-6) | |
| 13 | UNDERVOLTAGE | Reduce the number of connected appliances, especially when air conditioners and battery chargers are running. | |
| 13 | Undervoltage | Output voltage; Loads; Fuel supply; Sense lead connections; Control plugs fully seated; Sense leads fully seated in connector to control | Check: Output voltage; Loads; Fuel supply; Sense lead connections; Control plugs fully seated; Sense leads fully seated in connector to control |
| 13 | Undervoltage — Controller unable to maintain rated voltage | Controller unable to maintain rated voltage | Push line circuit breaker (Page 2-2) to OFF, start the genset and measure output voltage. If output voltage is normal, reduce the number of connected appliances, especially when air conditioners and battery chargers are running. If output voltage is low, test and service the generator (Page 5-2) as necessary; Replace controller A1 (Page 4-1) |
| 14 | High AC Frequency — After the starter was engaged Frequency jumped to more than 70 Hz for 40 milliseconds or to more than 2% over nominal for 6 seconds | Check for a tripped generator set circuit breaker, reset if necessary, and run with fewer loads. (A breaker tripping under load can cause generator set frequency to overshoot.); check all fuel fittings and filters for fuel and air leaks and tighten as necessary. (Air bubbles can disrupt frequency.) | |
| 14 | High AC frequency — After the starter was engaged Frequency jumped to more than 70 Hz for 40 milliseconds or to more than 2% over nominal for 6 seconds | After the starter was engaged Frequency jumped to more than 70 Hz for 40 milliseconds or to more than 2% over nominal for 6 seconds | Check for a tripped genset circuit breaker, reset it if necessary, and run with fewer connected loads. (A breaker tripping under load can cause genset frequency to overshoot.); Check all fuel fittings for fuel and air leaks and tighten as necessary and reprime. (Air bubbles can disrupt frequency.) |
| 14 | OVERFREQUENCY | 1. If the line circuit breaker or any other circuit breaker has tripped, start the genset before resetting the breaker. (Frequency can overshoot when a circuit breaker trips under load.) If the genset continues to run, turn off or disconnect all loads, reset the breaker and bring the loads on one at a time without overloading the genset. 2. Tighten loose fuel line fittings so that air cannot be drawn in by genset lift pump suction. 3. Prime the fuel system to remove air in the fuel lines (Page 8). | |
| 14 | Overfrequency | Engine speed; Loads; Governor actuator operation; Fuel supply; Control plugs fully seated; Quad leads fully seated in connector to control; Quad winding resistance | Check: Engine speed; Loads; Governor actuator operation; Fuel supply; Control plugs fully seated; Quad leads fully seated in connector to control; Quad winding resistance |
| 14 | Overfrequency — Engine governor unable to maintain rated frequency | Engine governor unable to maintain rated frequency | If the line circuit breaker or any other circuit breaker has tripped, start the genset before resetting the breaker. (Frequency can overshoot when a circuit breaker trips under load.) If the genset continues to run, turn off or disconnect all loads, reset the breaker and bring the loads on one at a time without overloading the genset; Tighten loose fuel line fittings so that air cannot be drawn in by genset lift pump suction; Prime the fuel system to remove air in the fuel lines (Page 2-3); Remove the governor actuator and replace it if malfunctioning (Page 4-8); Disconnect connector P1 (black) from controller A1 (Page 4-1) and measure resistance between Pin 5 and A12+ and between Pin 12 and A12-. If either lead is open, check for a missing, bent or corroded pin or faulty wiring and repair as necessary; Replace controller A1 (Page 4-1) |
| 15 | Low AC Frequency — During normal operation Frequency fell to less than 90% of nominal for more than 8 seconds | Push the generator set line circuit breaker OFF and de-energize the PTO clutch, if so equipped. If the generator set now runs, reduce the number of electrical and mechanical (PTO) loads, especially those with high motor starting loads, such as air conditioners; check the fuel tank and fill as necessary. (Note: The arrangement of pickup tubes in the fuel supply tank probably is such that the generator set will run out of fuel before the propulsion engines.); prime the engine fuel system for at least 30 seconds (p. 3-3); remove combustion air or exhaust system blockages; check all fuel fittings for fuel and air leaks and tighten as necessary. (Air bubbles can disrupt frequency.); replace fuel filters (p. 4-6); check for contaminated fuel by connecting to a source of known fuel quality | |
| 15 | Low AC frequency — During normal operation Frequency fell to less than 90% of nominal for more than 8 seconds | During normal operation Frequency fell to less than 90% of nominal for more than 8 seconds | Push the genset line circuit breaker OFF. If the genset now runs, reduce the number of loads, especially those with high motor starting loads such as air conditioners; Check fuel level and fill as necessary; Prime the engine fuel system for at least 30 seconds (p. 3-3); Check all fuel fittings for fuel and air leaks, tighten as necessary and reprime. (Air bubbles can disrupt frequency.); Replace the fuel filters and reprime (p. 4-5) |
| 15 | Low AC frequency — During normal operation Frequency fell to less than 90percent of nominal for more than 8 seconds | Push the generator set line circuit breaker OFF. If the generator set now runs, reduce the number of loads, especially those with high motor starting loads such as air conditioners; Check the fuel tank and fill as necessary. (Note: The arrangement of pickup tubes in the fuel supply tank probably is such that the generator set will run out of fuel before the propulsion engines.); Remove combustion air or exhaust system blockages; Prime the engine fuel system for at least 30 seconds (p. 3-3); Check all fuel filters and fittings for fuel and air leaks, tighten as necessary and reprime. (Air bubbles can disrupt frequency.); Replace the fuel filters and reprime (p. 4-6) | |
| 15 | Underfrequency | Engine speed; Loads; Governor actuator operation; Fuel supply; Control plugs fully seated; Quad leads fully seated in connector to control; Quad winding resistance | Check: Engine speed; Loads; Governor actuator operation; Fuel supply; Control plugs fully seated; Quad leads fully seated in connector to control; Quad winding resistance |
| 15 | Underfrequency — Engine governor unable to maintain rated frequency | Engine governor unable to maintain rated frequency | Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners; Check the fuel tank and fill as necessary. (Note: The arrangement of pickup tubes in the fuel supply tank probably is such that the genset will run out of fuel before the propulsion engines.); Remove any blockage in the combustion air inlet (front grille) or exhaust system; Tighten loose fuel line fittings so that air cannot be drawn in by genset lift pump suction; Drain and/or replace the fuel filter (Page 3-5) and prime the fuel system (Page 2-3); Drain and/or replace fuel supply system filters and prime the fuel system (Page 2-3); Conduct a fuel pump flow test and service as necessary (Page 6-3); Remove the governor actuator and replace it if malfunctioning (Page 4-8); Disconnect connector P1 (black) from controller A1 (Page 4-1) and measure resistance between Pin 5 and A12+ and between Pin 12 and A12-. If either lead is open, check for a missing, bent or corroded pin or faulty wiring and repair as necessary; Service the fuel injectors and injection pump as necessary (Engine Workshop Manual 981-0528); Check fuel injection timing (Engine Workshop Manual 981-0528); Replace controller A1 (Page 4-1) |
| 17 | Over-prime — Prime mode exceed 5 minutes | Prime mode exceed 5 minutes | Check for and remove any object that may be holding either control switch (remote or local) in the prime position; Disconnect remote connector P4 and check for continuity between Pins 4 and 2 when the remote switch is not held at STOP. If there is continuity, repair or reconnect the remote wiring as necessary; Disconnect control switch S4 and check for continuity between terminals 1 and 2 when the switch is not held at STOP (Page 4-4). If there is continuity, replace switch S4 |
| 17 | Overprime | Battery voltage; Fuel supply; Start/stop switch (local and remote); Shorted wiring | Check: Battery voltage; Fuel supply; Start/stop switch (local and remote); Shorted wiring |
| 2 | LOW OIL PRESSURE | Add engine oil or drain excess oil, as necessary (Page 14). | |
| 2 | Low Oil Pressure | Oil level; Broken or loose sender lead; Pressure sender open | Check: Oil level; Broken or loose sender lead; Pressure sender open |
| 2 | Low Oil Pressure — Low oil pressure | Check the engine oil level and add or drain oil as necessary (p. 4-3); repair any oil leaks | |
| 2 | Low oil pressure — First-level shutdown—Low oil pressure | Low oil pressure | Add engine oil or drain excess oil, as necessary (Page 3-3); Disconnect connector P1 (black) from controller A1 (Page 4-1) and measure resistance between Pin 10 and B- (ground). If resistance is greater than 257 Ohms, check for a missing, bent or corroded pin or faulty wiring or loose ring terminal on sender E1 (Page 4-5). Repair as necessary; Replace the sender with a gauge, ground the sender wire (to keep engine running) and start the engine. Shut down the engine immediately if there is no oil pressure. A. If engine oil pressure is less than 14 psi (98 kPa), service the oil lubricating system (Engine Workshop Manual 981-0528). B. If engine oil pressure is at least 14 psi (98 kPa), test oil pressure sender E1 (Page 4-5) and replace if necessary. Replace controller A1 (Page 4-1) if sender E1 is in working order |
| 2 | Low oil pressure — Low oil pressure | Low oil pressure | Check engine oil level, add or drain oil as necessary and repair any leaks (p. 4-3) |
| 22 | Actuator Overload | Load; Fuel supply; Intake restriction; Governor actuator operation | Check: Load; Fuel supply; Intake restriction; Governor actuator operation |
| 22 | Governor Overload — Maximum allowable time at full-duty cycle was exceeded | Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners; check the fuel tank and fill as necessary. (Note: The arrangement of pickup tubes in the fuel supply tank probably is such that the generator set will run out of fuel before the propulsion engines.); remove combustion air or exhaust system blockages; check all fuel fittings for fuel and air leaks and tighten as necessary; replace fuel filters (p. 4-6); check for contaminated fuel by connecting to a source of known fuel quality | |
| 22 | Governor overload — Maximum allowable time at full-duty cycle was exceeded | Maximum allowable time at full-duty cycle was exceeded | Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners; Check the fuel tank and fill as necessary. (Note: The arrangement of pickup tubes in the fuel supply tank probably is such that the genset will run out of fuel before the propulsion engines.); Remove any blockage in the combustion air inlet (front grille) or exhaust system; Tighten loose fuel line fittings so that air cannot be drawn in by genset lift pump suction; Drain and/or replace the fuel filter (Page 3-5) and prime the fuel system (Page 2-3); Drain and/or replace fuel supply system filters and prime the fuel system (Page 2-3); Conduct a fuel pump flow test and service as necessary (Page 6-3); Remove the governor actuator and replace it if malfunctioning (Page 4-8); Service the fuel injectors and injection pump as necessary (Engine Workshop Manual 981-0528); Check fuel injection timing (Engine Workshop Manual 981-0528); Replace controller A1 (Page 4-1) |
| 23 | Faulty Oil Pressure Sender | Oil level; Grounded or shorted sender lead; Sender resistance (low) | Check: Oil level; Grounded or shorted sender lead; Sender resistance (low) |
| 23 | Faulty Oil Pressure Sender — Controller sensed grounded sender | See an authorized Onan service representative | |
| 23 | Faulty oil pressure sender (Controller sensed grounded sender) | Refer to Pages A-1 through A-5, as appropriate; If loose, tighten the ring terminal on oil pressure sender E1 (Page 5-6) (this fault will occur if a loose ring terminal touches grounded metal); Repair wiring as necessary to eliminate the ground path; Check electrical resistance through sender E1 and replace the sender if resistance is not between 227 and 257 ohms (0 psi) when the engine is stopped; Replace the genset controller (p. 5-1) | |
| 23 | Faulty oil pressure sender — Controller sensed grounded sender | Controller sensed grounded sender | Disconnect connector P1 (black) from controller A1 (Page 4-1) and measure resistance between Pin 10 and B- (ground). If there is a short to ground, repair the wiring or test and replace sender E1 (Page 4-5), as necessary |
| 24 | Faulty Temperature Sender | Coolant level; Open or loose sender lead; Sender resistance (high) | Check: Coolant level; Open or loose sender lead; Sender resistance (high) |
| 24 | Faulty Temperature Sender — Controller sensed open sender | See an authorized Onan service representative | |
| 24 | Faulty temperature sender (Controller sensed open sender) | See an authorized Cummins Onan service representative. | |
| 24 | Faulty temperature sender — Controller sensed open sender | Controller sensed open sender | Tighten the ring terminal on sender E2 (Page 4-5) if loose. (For isolated-ground applications only, connect flag terminal E2-2 if loose. Also check continuity between E2-2 and B- [ground] and repair wire as necessary.); Measure resistance across sender E2 (Page 4-5) and replace it if open; Disconnect connector P1 (black) from controller A1 (Page 4-1) and check continuity between Pin 9 and ring terminal E2-1. Repair the wiring as necessary if open |
| 27 | Loss of AC Voltage Sense — The generator set Controller lost VAC sensing during normal voltage regulation when the field was functioning normally and frequency was at least 40 Hz | See an authorized Onan service representative | |
| 27 | Loss of AC Voltage Sense — The genset Controller lost VAC sensing during normal voltage regulation when the field was functioning normally and frequency was at least 40 Hz | See an authorized Onan service representative | |
| 27 | Loss of AC voltage sense (The generator set Controller lost VAC sensing during normal voltage regulation when the field was functioning normally and frequency was at least 40 Hz) | See an authorized Cummins Onan service representative. | |
| 27 | Loss of AC voltage sense — The genset Controller lost VAC sensing during normal voltage regulation when the field was functioning normally and frequency was at least 40 Hz | The genset Controller lost VAC sensing during normal voltage regulation when the field was functioning normally and frequency was at least 40 Hz | See an authorized Onan service representative |
| 27 | Loss of Voltage Sense | AC output; Sense lead connections; Control plugs fully seated; Sense leads fully seated in connector to control; Field windings; Proper field resistance reading, open to ground; Brush condition and contact; Grounded or shorted main windings | Check: AC output; Sense lead connections; Control plugs fully seated; Sense leads fully seated in connector to control; Field windings; Proper field resistance reading, open to ground; Brush condition and contact; Grounded or shorted main windings |
| 27 | Loss of voltage sense — Controller unable to sense output voltage | Controller unable to sense output voltage | Disconnect connector P3 (green) from controller A1 (Page 4-1) and check continuity between Pin 11 and S1 and between Pin 12 and S2. If open, check for missing, bent or corroded pins and faulty wiring and repair as necessary; Test and service the generator (Page 5-2) as necessary; Replace controller A1 (Page 4-1) |
| 29 | High Battery Voltage | Battery voltage; Battery connections; Battery charge rate | Check: Battery voltage; Battery connections; Battery charge rate |
| 29 | High Battery Voltage — During startup the generator set Controller sensed that battery system voltage was greater than 19.2 volts if 12 VDC system or 32.2 volts if 24 volt system | Check battery bank connections and reconnect if necessary for 12 volts or 24 volts, depending on generator set model; select a lower battery booster charge rate (external charging system) | |
| 29 | High Battery Voltage — During startup the genset Controller sensed that battery system voltage was greater than 19.2 volts if 12 VDC system or 32.2 volts if 24 volt system | Check battery bank connections and reconnect if necessary for 12 volts or 24 volts, depending on genset model; Select a lower battery booster charge rate (external charging system) | |
| 29 | High battery voltage (During startup the generator set Controller sensed that battery system voltage was greater than 19.2 volts if 12 VDC system or 32.2 volts if 24 volt system) | Check battery bank connections and reconnect if necessary for 12 volts or 24 volts, depending on generator set model; Select a lower battery booster charge rate (external charging system). | |
| 29 | High battery voltage — Battery system at more than 19.2 volts if 12 VDC system, or 38.4 volts if 24 volt system | Battery system at more than 19.2 volts if 12 VDC system, or 38.4 volts if 24 volt system | Check battery bank connections and reconnect if necessary to supply 12 volts or 24 volts, as appropriate; Select a lower external battery boost charge rate |
| 29 | High battery voltage — During startup the genset Controller sensed that battery system voltage was greater than 19.2 volts | During startup the genset Controller sensed that battery system voltage was greater than 19.2 volts | Check battery bank connections and reconnect if necessary for 12 volts; Select a lower battery booster charge rate |
| 3 | SERVICE CHECK | Check the second-level shutdown code by pressing STOP once. The second-level shutdown code will have two-digits. The shutdowns are listed below in numerical order. | |
| 3 | Service Check — A fault with a 2-Digit Fault Code Number occurred | Check the 2-Digit fault code by Pushing and Releasing Stop. The 2-Digit fault will be one of the following in this table. (Does not apply to Digital Display.) |
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.