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RDC2 Controller

The RDC2 is a generator-set controller. It is used on generator sets from Generac and Kohler, including the 10RESV, 12RESV, 8RESV and 10RESV.

125
Generator sets
2
Brands
7–60 kW
Power range
4
Fuel types

Generator sets using this controller

125

Used across brands: Generac, Kohler

Also fitted to: Kohler 10RESV/10RESVL, Kohler 12RESV/12RESVL, Kohler 14/20RCA/RCAL, Kohler 14/20RES, Kohler 14/20RESA/RESAL, Kohler 14RCA/14RCAL, Kohler 14RCA/L, Kohler 20 kW Models, Kohler 20RCA/20RCAL, Kohler 20RCA/L, Kohler 20RESA/20RESAL/20RESC/RESCL, Kohler 20RESC/RESCL, Kohler 26RCA/26RCAL, Kohler 26RCA/L, Kohler 26RCA/RCAL, Kohler 8RESV/8RESVL, Kohler Model RESA/L or RESC/L, Kohler RESA/RESAL, Kohler TP-6984 4/26f.

Troubleshooting

60

Fault codes

CodeMeaningCauseRemedy
Battery Low WarningsLow battery voltage warnings are displayed on the controller display.Check the battery connections and ensure they are secure. Replace the battery if it is low on charge.
BusDeadLiveThe bus is measured to be dead when one of the generators is supposed to be supplying voltage to the bus (closed contactor)Bus metering V9A and V9B connections to V9 of paralleling protection harness are connected incorrectly.
BusDeadLiveThe bus is measured to be dead when one of the generators is supposed to be supplying voltage to the bus (closed contactor).Bus metering V9A and V9B connections to V9 of paralleling protection harness are connected incorrectly.
BusLiveDeadThe bus is measured to be live when no generators are connected to it (both contactors open).Bus metering V9A and V9B connections to V9 of paralleling protection harness are connected incorrectly.
CfgModelNumThe two generators that are intended to be paralleled have incompatible model numbers.Incorrect configuration of one of the generators. Different generator types. The paralleled generator sets must be the same kW model. (i.e. two 14 kW or two 20 kWor 26 kW models).
CfgSysVoltThe system voltage of the two generators intended to be paralleled is not the same.One of the two generators is incorrectly configured. Intermittent connections on RBUS network wiring.
ConCheckFailFailure to Auto-Discover APM connections.Wires 9A and 9B crossed between the generators. Wires 9A or 9B not connected.
ConNotDetermAPM connection auto-discovery is not complete. This means that the generator does not know which contactor is connected to it.Generators not yet started in RUN with other generator in OFF. See the APM instruction sheet for instructions to perform the auto-discovery procedure.
ContactorOkSuccessful auto-discovery of APM connections.Auto-discovery was activated by placing other generator in OFF and this generator in RUN.
CoolntTemp 0Coolant temperature is extremely high.Check coolant level. Check radiator and fans for obstruction. Contact an authorized distributor/dealer for service and provide the fault code.
CoolntTemp 3The ECM reported a problem with the coolant temperature sensor reading: 3 = high voltage.Contact an authorized distributor/dealer for service and provide the fault code.
CoolntTemp 4The ECM reported a problem with the coolant temperature sensor reading: 4 = low voltage.Contact an authorized distributor/dealer for service and provide the fault code.
CoolntTemp 5The ECM reported a problem with the coolant temperature sensor reading: 5 = open circuit.Contact an authorized distributor/dealer for service and provide the fault code.
Crank LostCrankshaft Position Sensor (CPS) timeout error occurred.Contact an authorized distributor/dealer for service and provide the fault code.
Current A High WarningOver Current ParalleledPress AUTO or OFF *
Emerg StopThe emergency stop switch has been activated, or there has been an open circuit in the wiring.Contact an authorized distributor/dealer for service.
Eng Speed HighEngine speed exceeds 115% of the normal running speed for more than 0.3 seconds.Contact an authorized distributor/dealer for service.
Eng Speed LowEngine speed drops below 85% of the normal running speed for more than 3 seconds.Reduce the load by turning off appliances. Contact an authorized distributor/dealer for service.
ErraticSigThe power metering on this controller gives a signal that is not consistent with the system configuration. Reversing the power direction does not resolve the problem.Bad wiring to the CT. Too much tension on wires from the CT to the controller.
Exer Not SchExercise Not Scheduled. No exercise has been scheduled on the RDC2 controller.See Section 2.5 for instructions to set the exerciser.
Faults Related to ParallelingParalleling issues occur, such as incorrect synchronization or failure to maintain parallel operation.Verify that all paralleling settings are correct in the controller parameters. Check the paralleling cables and connections for any faults.
Frequency HighGoverned frequency exceeds 110% of the system’s frequency setpoint for more than 10 seconds.Contact an authorized distributor/dealer for service.
Frequency High WarningOver Frequency ParalleledPress AUTO or OFF *
Frequency LowGoverned frequency falls below 90% of the system frequency setting for more than 10 seconds, or 1 Hz below the system frequency setting for more than 60 seconds.Reduce the load by turning off appliances and restart the generator set. Contact an authorized distributor/dealer for service.
Frequency Low WarningUnder Frequency ParalleledPress AUTO or OFF *
IAT High 1Engine manifold air temperature is too high.Contact an authorized distributor/dealer for service and provide the fault code.
IAT Volt LoThe ECM reported an Engine Air Temperature/Manifold Absolute Pressure Sensor (TMAP) error.Contact an authorized distributor/dealer for service and provide the fault code.
Lo Crank VltLow cranking voltage. Battery voltage falls below 60% of system battery voltage for more than 6 seconds while the starter is engaged.Charge or replace the battery.
Locked RotorNo engine rotation is sensed during cranking. Shuts down 3 seconds after the fault is detected.Check the battery. Check for loose connections. Check for obstruction of alternator or engine. Contact an authorized distributor/dealer for service.
LossOfComAPMThe Automatic Paralleling Module has stopped communicating on RBUS. (An APM was detected on the RBUS network but is no longer communicating).APM is unplugged. Primary controller is powered down. Check the battery connections. See previous page for more information. Intermittent connections on RBUS network wiring.
LossOfComAPMThe Automatic Paralleling Module has stopped communicating on RBUS. (An APM was detected on the RBUS network but is no longer communicating.)APM is unplugged. Primary controller is powered down. Check the battery connections. See previous page for more information. Intermittent connections on RBUS network wiring. Check RBUS communication connections.
LossOfComm2Communication Lost with Secondary Controller
LossOfComm2The primary controller has lost communication with the secondary controller. (A secondary controller was detected, then communication was lost.)RBUS disconnected, secondary controller battery disconnected, updating firmware in secondary controller, or intermittent RBUS connections.
LossOfFieldThis generator has absorbed more than 25% reactive power (magnetic excitation current) for 20 seconds Generator voltage on this generator is not calibrated correctly. Generator voltage on other generator is not calibrated correctly. Bus voltage on this generator is not calibrated correctly. Bus voltage on the other generator is not calibrated correctly.
LossOfFieldThis generator has absorbed more than 25% reactive power (magnetic excitation current) for 20 seconds.Generator voltage on this generator is not calibrated correctly. Generator voltage on other generator is not calibrated correctly. Bus voltage on this generator is not calibrated correctly. Bus voltage on the other generator is not calibrated correctly.
Main Power Overload ShutdownThe generator shuts down due to a main power overload.Check the circuit breaker and ensure it is not tripped. If necessary, replace the circuit breaker.
MainPwrOverLMain power overload. An over current fault on the 70 controller power output (short circuit).Check for shorted run relay. Check wiring for short circuits. Contact an authorized distributor/dealer for service.
Maint Req’dEngine maintenance is due.Check the maintenance schedule in the operation manual for tasks such as changing the oil, spark plugs or the air filter.
MeterUnknownThis generator does not know if the metering is connected or the orientation of the connection. This means that the generators can’t share load accurately until this information is known.System commissioning and startup not yet complete. See the APM instructions.
MeteringOkThe generator has verified that the metering is connected correctly and that the direction is consistent with expected power direction.Status message indicates that the CT is connected to the generator correctly.
MeteringOkThe generator has verified that the metering is connected correctly and that the direction is consistent with expected power direction. Status message indicates that the CT is connected to the generator correctly.
NoCurrentThe generator has applied load (using the other generator) and has observed no current on the power sensing inputs.The CT is not connected to the controller. The output leads from the generator do not go through the CT in the correct direction. See the APM instructions.
Not in AutoThe generator set is not in Automatic (standby) mode. Remote start and stop commands from a transfer switch or remote switch will be ignored.Press AUTO to place the generator set in Automatic mode, when appropriate.
Oil Pres LowThe engine ECM indicates low oil pressure.Note: The low oil pressure shutdown does not protect against low oil level. Check the engine oil level regularly as recommended in Section 4. Check for leaks in the lubrication system. Check the oil level and add oil if the level is low. Check the oil pressure switch and wiring.
Over CrankThree unsuccessful starting attempts.Check the fuel supply, spark plug, and battery. Check for loose connections. Contact an authorized distributor/dealer for service.
PrimLoopOpnIgnition coil 1 voltage is below normal or there is an open circuit.Check the battery voltage. Contact an authorized distributor/dealer for service and provide the fault code.
PrimLoopShtIgnition coil 1 voltage is abnoContact an authorized distributor/dealer for service and provide the fault code.
Reactive Power Low WarningLoss of Field ParalleledPress AUTO or OFF *
Real Power High WarningOver Power ParalleledPress AUTO or OFF *
Real Power Low WarningReverse Power ParalleledPress AUTO or OFF *
SyncFailureThe generator has been attempting to synchronize for over 2 minutes without success.Generator is hunting. Advanced speed control settings need adjustment. Load is changing frequently to disturb the online generator.
TP-6905 4/16Generator set serial number is unavailable.Contact an authorized distributor/dealer for service. See section 3.11.
TP-7092Engine starting battery is deadCheck and clean the battery, terminals, cables. If necessary, recharge or replace the battery.
TP-7092Loose connectionsTighten all loose connections
TP-7092Open circuit breakerCheck and close any open circuit breakers
TP-7092The controller displays fault messages
Voltage L1-L2 High WarningOver Voltage ParalleledPress AUTO or OFF *
Voltage L1-L2 Low WarningUnder Voltage ParalleledPress AUTO or OFF *
Volts L1-L2Generator voltage high. Output voltage exceeds 120% of the system nominal voltage for more than 2 seconds.Contact an authorized distributor/dealer for service.
Volts L1-L2Generator voltage low. Output voltage falls below 80% of the nominal system voltage for more than 10 seconds.Reduce the load and restart the generator set. Model 20RCA/20RCAL only: Check enclosure thermostat and reset if tripped. See Section 5.6.

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.