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ProService Generator Repairs

Controller guide

Generator Controllers: Brands, Alarms and Error Codes

A generator controller is the module that monitors the engine, shows alarms, and decides when the set may start. Find the alarm on your screen below and you will know where the fault is likely to be. When the module itself needs work, we diagnose, reprogram or replace it on site across Gauteng.

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  • DSE, SmartGen, Datakom, ComAp, Generac
  • Common alarms explained
  • Error codes decoded
  • Onsite across Gauteng
Yellow open diesel generator set beside a red control cabinet with digital controller and breakers in a basement plant room

What does a generator controller do?

The controller watches the engine and the output, raises an alarm when a reading goes wrong, and starts or stops the set. These terms come up on almost every controller job.

Controller
The module that reads sensors, displays alarms, and starts or stops the engine when its settings allow it.
AMF
Automatic mains failure. An AMF controller starts the set by itself when it sees the mains supply fail.
ATS
The automatic transfer switch. It moves your building between mains and generator, and works alongside the controller.
Warning
An alarm that lets the engine keep running while it asks for attention.
Shutdown
An alarm that stops the engine to protect it, such as low oil pressure or high temperature.
Auto-start
A start without anyone pressing a button, usually after a mains failure or a remote start signal.
Configuration
The settings for sensors, timers, alarms and start behaviour, matched to the generator the module controls.
SPN and FMI
The two numbers an electronic engine uses to report a fault on J1939: the part or reading, and how it failed.

What do generator controller alarms mean?

An alarm tells you what the controller saw, not which part failed. Here are the alarms we see most often, what each one means, and where we look first. We keep every shutdown connected while we test, so the engine stays protected.

  • Fail to start

    The engine cranked for its set number of attempts and did not fire.

    What we check: Fuel supply, the fuel solenoid, battery voltage while cranking and the start signal.

  • Low oil pressure

    The oil pressure switch or sender reported pressure below the shutdown setting.

    What we check: The oil level and the real pressure on a gauge, then the sender and its wiring.

  • High coolant temperature

    The engine ran hotter than its shutdown setting.

    What we check: Coolant level, radiator airflow, the fan belt and the load, once the engine has cooled.

  • Over speed or under speed

    Engine speed moved outside its limits.

    What we check: The governor, the fuel supply and the speed sensor.

  • Low or high frequency

    Output frequency left its limits, usually because engine speed changed.

    What we check: The governor, large load steps and fuel delivery.

  • Low or high voltage

    Output voltage left its limits.

    What we check: The AVR, the excitation, the alternator and the voltage sensing wires.

  • Charge alternator failure

    The engine’s charge alternator is not charging the battery while the set runs.

    What we check: The belt, the alternator output and the excitation wire.

  • Low battery or charger fault

    Battery voltage dropped, or the mains battery charger reported a fault.

    What we check: The battery, the charger, its fuse and the cabling.

  • Emergency stop

    An emergency stop button is pressed, or its circuit is open.

    What we check: Which button or wire opened the circuit, before we reset it safely.

  • Fail to stop

    The engine kept running after a stop command.

    What we check: The fuel solenoid, the stop circuit and the speed signal.

  • Mains failure

    The controller sees that the mains supply has failed. On an AMF set, this is the signal to start.

    What we check: If the set did not start: the controller mode, the mains sensing and the start delay.

  • Sensor open circuit

    A sensor wire is broken or unplugged, so the reading is missing.

    What we check: The sender, its plug and the cable back to the module.

  • CAN or ECU fault

    The controller lost contact with the engine ECU, or the ECU sent a fault code.

    What we check: The CAN wiring and the code the ECU reports.

  • Maintenance due

    The service timer reached its interval.

    What we check: Book a service. We reset the timer once the work is done.

What to do when your controller shows an alarm

  1. Photograph the screen before you press anything, including any alarm history.
  2. Note what the generator was doing: starting, running on load, or standing.
  3. Check what you can see safely from outside the canopy, such as the fuel gauge and any leak under the set.
  4. Leave the panel closed and every protection connected.
  5. If a shutdown alarm comes back after a reset, leave the generator off and call us on 082 057 4605.

How to read a generator error code

Most industrial controllers show the alarm as text, such as Low Oil Pressure or Fail to Start, often with a short alarm history. Photograph the whole list, because the first alarm usually explains the ones after it.

Electronic engines that talk to the controller over CAN or J1939 add their own fault codes. Each code has an SPN, which identifies the part or reading, and an FMI, which describes how it failed, such as a reading that is too high, too low or missing. Send us both numbers with the engine make.

Residential standby controllers, such as the Generac Evolution range, keep an alarm log with a code and the date it happened. That log shows whether today’s fault is new or has been building for weeks.

Controller brands

Generator controller brands we work with

SmartGen, Deep Sea Electronics, Datakom and Generac are the controllers we meet most often in Gauteng. Each card opens the section for that family.

Also on our list

Other controller families

We also work on these modules. Send a photo of yours and we will identify it.

SmartGen Generator Controllers

SmartGen controllers handle manual and automatic starting, AMF, engine and generator monitoring, alarms and protection, and CAN or J1939 engine communication on models that support it.

The SmartGen models we meet most often include:

  • HGM4010N and HGM4020N
  • HGM6110N and HGM6110NC
  • HGM6120N, HGM6120NC and HGM6120CAN
  • HGM7120N
  • HGM7220 and HGM7220N
  • HGM9320CAN
  • HGM9510 and HGM9530

When a SmartGen module is damaged or no longer supported, we fit a compatible replacement or upgrade and set it up for your engine.

Deep Sea Electronics (DSE) Generator Controllers

DSE controllers handle monitoring, automatic start, AMF and protection, from simple start modules to synchronising controllers. We start every DSE job by reading the alarm on the display and checking the wiring around the module.

The DSE units we meet most often include:

  • DSE3110
  • DSE4520 MKII
  • DSE6020 MKII
  • DSE6110 MKIII
  • DSE6120 MKIII
  • DSE7310 MKII and DSE7320 MKII
  • DSE7410 MKII and DSE7420 MKII
  • DSE8610 MKII and DSE8620 MKII

We also assess older DSE generations for repair, replacement or an upgrade. Send a photo of the module fitted to your set. Our Deep Sea controller repairs page explains the difference between auto start and auto mains failure modules, and the AMF sequence step by step.

Datakom Generator Controllers

Datakom controllers cover generator monitoring, AMF, engine protection and automatic starting. We see the D-series and DKG modules most often, including the D-100, D-200, D-300, D-500, D-500 Lite, DKG-307, DKG-527, DKG-537, DKG-547 and DKG-557.

When an older Datakom module is obsolete or its hardware has failed, we recommend a replacement or upgrade and explain why before we order parts.

Generac Generator Controllers

Generac standby generators usually carry Generac’s own controller instead of a generic industrial module. We work on Evolution, Evolution 1.0, Evolution 2.0 and Nexus controls, and on older pre-Nexus controls still in service.

The right fix depends on the generator model, the controller generation and its condition, programming access and the replacements available. For the engine side, see Generac gas generator repairs and Generac diesel generator repairs.

Other generator controllers we work on

These families turn up less often, mainly on larger or imported sets. A clear photo of the module is usually enough for us to identify it.

ComAp

InteliNano, InteliLite and InteliGen controllers, from small standby sets to larger installations.

DEIF

AGC and SGC genset controllers.

Woodward

The easYgen family of generator controls.

Kohler / Rehlko

RDC and DC-type controls on Kohler standby generators.

Lovato Electric

The RGK generator controller family.

Kutai Electronics

Generator and AMF control modules.

Controller work

Controller jobs explained

Each job solves a different problem. A reprogram fixes settings, a replacement fixes failed hardware, and an alarm diagnosis fixes the fault the alarm is reporting.

  • Yellow silent diesel generator control panel with a basic digital controller, starter switch and circuit breakers

    Controller Fault Diagnosis

    We trace the alarm, the blank screen or the failed start to its cause before we condemn the module.

  • SmartGen genset controller reading 240 V, 51.5 Hz and 1543 rpm with the message gens normal running

    Controller Repair

    We check the power, wiring, inputs and connections, and repair the module when it can still be saved.

  • SmartGen controller, indicator lamps and output breaker on a pale grey canopy panel above a louvred vent

    Controller Replacement

    We fit a compatible replacement for a damaged, obsolete or uneconomical module.

  • Control panel of a blue JDP10000E single-phase generator showing key switch, voltmeter and 7000 W rating

    Controller Reprogramming

    We rewrite the settings with the maker’s software where the model and the access allow it.

  • Orange control box with a Deep Sea Electronics controller and emergency stop inside an open blue canopy door

    Controller Configuration

    We set the sensors, alarms, inputs and automatic start for the generator the module controls.

  • One person in a bucket hat working inside a stripped silent diesel generator, tools and parts on the ground

    Controller Upgrade / Retrofit

    We fit a newer module into an older panel once we have confirmed it is compatible.

  • SmartGen controller showing a failed to start alarm with 0 V, 0 rpm and 12.8 V battery, on an orange panel

    Alarm Diagnosis

    We record the alarm and fix its cause, so it stays cleared.

  • SmartGen genset controller showing a maintenance warning at 1557 rpm, with key switch and indicator lamps

    Automatic Start / AMF Setup

    We configure automatic mains-failure starting on controllers that support it.

  • SmartGen controller with key switch and indicator lights above a taped-on ATS wiring instruction sheet

    ATS Integration

    We test the controller and the transfer switch as one sequence, from mains failure to load transfer.

  • Yellow silent diesel generator panel with key starter, hour meter, voltmeter, ATS socket and two 230 V outlets

    CAN / J1939 Configuration

    We set up engine communication on controllers and engines that use CAN or J1939.

  • Inside a generator control panel: ESD5500E speed control unit, power supply, breakers and labelled terminal wiring

    Controller Commissioning

    After setup, we watch the start, the alarms and the transfer work under real conditions.

  • Deep Sea Electronics controller showing about 245 V on each of three phases, with Stop, Auto and Start buttons

    Maintenance Alarm Reset

    We reset the service timer once the service it calls for has been done.

Does your controller need repair, reprogramming or replacement?

Reprogramming suits a module that powers up and responds but has wrong or lost settings. Repair suits a module let down by its supply, wiring or connections. Replacement suits a module that is burnt, obsolete or will not hold its configuration.

We test before we recommend any of the three. Our generator controller repairs service covers the module itself, and our control panel repairs service covers the relays, breakers and wiring around it. Control panel repair or reprogramming typically costs R3,500 to R14,000.

What should I send before booking a controller repair?

Send what you can before the visit. It helps us identify the module and bring the right tools.

  • A clear photo of the controller
  • The controller make and model
  • The generator make and model
  • A photo of the generator data plate
  • The engine data plate, where you can see it
  • A photo of the alarm on the screen
  • A short description of the problem

With that, we can tell you whether the visit is likely to be a diagnosis, a reprogram or a replacement before we arrive.

Common Questions

Generator controller questions

What does a generator controller do?

It monitors the engine and the alternator, shows alarms, and starts or stops the generator. An AMF controller also starts the set automatically when the mains fails.

What do the alarms on my generator controller mean?

Each alarm names the condition the controller saw, such as low oil pressure, high coolant temperature, fail to start or low voltage. It tells us where to test first, not which part to replace.

What is the difference between a warning and a shutdown?

A warning lets the generator keep running and asks for attention. A shutdown stops the engine to protect it, and the cause needs checking before the set runs again.

How do I read an error code from a CAN engine?

On J1939 engines the ECU reports a fault as an SPN, which names the part or reading, and an FMI, which describes how it failed. Photograph both numbers and send them to us.

Which controller brands do you work on?

Deep Sea Electronics (DSE), SmartGen, Datakom, ComAp and Generac most often, plus DEIF, Woodward, Cummins PowerCommand, Caterpillar EMCP, FG Wilson PowerWizard, Kohler, Lovato and Kutai modules.

Can I clear the alarm and keep running?

Only once the cause is fixed. Clearing a low oil pressure or high temperature shutdown and restarting can wreck the engine. Photograph the alarm and call us if it comes back.

Why does my generator start manually but not automatically?

Automatic starting needs the controller in auto mode, working mains sensing, a charged battery and, where fitted, a start signal from the ATS. Any of those can fail while the manual start still works.

What does a controller repair cost?

Control panel repair or reprogramming typically costs R3,500 to R14,000, depending on whether the module needs new settings, a repair or a replacement. You get a free written quote first.

Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.

Call 082 057 4605WhatsAppRequest a Quote

Related Pages

Controller repairs, panels and starting faults

What to send before we attend

These details help us plan the visit and bring the right parts. Send what you can on WhatsApp; if you can’t find the model number, we still book the visit.

Location
The suburb or site, so the visit can be booked in the right area.
Make and model
The generator brand and model, if they are known.
kVA
The size printed on the data plate.
Fuel type
Diesel, petrol, LPG, natural gas, or dual-fuel.
Controller model
The module name on the panel, when it is visible.
Fault or alarm
What the set does, and any text on the screen.
Photos
The generator, the data plate, and the controller or alarm. Send these on WhatsApp.

Free written quote

Need a generator controller looked at?

Send a photo of the controller screen and any alarm. We tell you what it means and whether the module needs repair, reprogramming or replacement.

Photos of the generator and the data plate can be sent on WhatsApp.

Add your email (optional)
  • Free written quote before any work starts
  • Callout fee waived when you accept the quote
  • 1-year workmanship guarantee

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What happens next

  1. We reply with questions about the generator, or to book a visit.
  2. A technician comes to you. For a breakdown we arrive within 1 hour.
  3. The fault is diagnosed on site and you get a written quote. No work starts until you accept it.

Charlie, lead technician: Degree in Mechanical Engineering, Degree in Electrical Engineering, Diesel Plant Fitter. Generator specialists since 2000.