Fault tool
Generator symptom finder
Tick what the generator is doing. For each symptom you will see several possible causes, what you can safely check without opening anything, the signs that mean you should stop using it, and the service it is usually booked as.
It is a guide, not a diagnosis. One symptom never proves which part has failed, and the finder gives no repair instructions.
Free to use · No login · Works on a phone
Choose a symptom to see possible causes, what you can safely check and when to stop using the generator.
Where the answers come from
The finder uses the same fault data as the fault-finding pages, so the two always agree. Each fault lists several causes because the same symptom can come from different systems. A technician’s tests decide which one applies.
Safety before you check anything
- Exhaust contains carbon monoxide, which you cannot see or smell. Run a portable generator outdoors only, away from doors, windows and vents, and never run any generator in a house, garage or other enclosed space.
- A standby generator set to automatic can start at any moment, when the mains fails or on its exercise timer. Keep the canopy closed and stay clear of fans, belts and the exhaust.
- Generator output, the changeover and the control panel can be live, and some parts hold stored electrical energy after shutdown. Leave panels, covers and wiring closed for us to open.
- The engine, exhaust and coolant stay hot after running. Never open a radiator or coolant cap on a hot engine.
- Do not refuel a running or hot generator. If you smell gas at a gas-fuelled set, do not operate switches; leave the area and contact your gas supplier.
Carbon monoxide guidance: US Consumer Product Safety Commission: Generators and engine-driven tools (carbon monoxide).
Full fault guides
- Generator not starting
- Generator cranks but will not start
- Generator starts then stops
- Generator running but not producing power
- Generator producing low voltage
- Generator voltage unstable or fluctuating
- Generator low or unstable frequency
- Generator trips or shuts down under load
- Generator overheating
- Generator blowing black smoke
- Generator blowing white smoke
- Generator blowing blue smoke
- Generator battery not charging
- Generator not starting automatically
- Generator low oil pressure
- Contaminated diesel in a generator
- Generator surging or hunting
- Generator knocking or making a strange noise
- Generator not switching back to mains
Limits
- The finder cannot see, hear or measure your generator. Only a technician’s tests can confirm a cause.
- Several faults can happen together. If more than one symptom fits, tick them all.
- If anything in the stop-use list applies, stop using the generator and call before trying anything else.
Related
Guides and services that go with this tool
Book a diagnosis visit
ProService Generator Repairs works onsite across Gauteng. Send the generator details on WhatsApp or call to arrange a visit.