Troubleshooting Iseki GEAS AT23-AT33 faults: the official tables plus practical experience
Fault with your Iseki GEAS AT? Below you'll find the complete troubleshooting tables from the factory manual, supplemented with a number of known points of attention from practice. Go through these tables first before having an expensive component replaced — often the problem lies in something small.
Suitable for the entire series: Iseki GEAS AT23, AT25, AT27, AT30, AT33, AT27N and AT33N.
Iseki GEAS AT23-AT33 engine won't start
| Symptom |
Possible cause |
Solution |
| Starter motor doesn't turn when "Starting" |
Clutch pedal not fully depressed |
Fully depress the clutch |
| Clutch pedal switch faulty |
Have it repaired/replaced by dealer |
| Battery discharged |
Charge battery |
| Terminals loose |
Tighten |
| Ground connection corroded |
Remove rust and tighten (with grease) |
| Ignition switch faulty |
Dealer |
| Starter motor faulty |
Dealer |
| Starter motor turns, but slowly |
Battery insufficiently charged |
Charge |
| Ground connection corroded |
Clean |
| Engine oil too thick/wrong viscosity |
Use correct viscosity |
| Fuel pump not working properly |
Check/replace fuse |
| Starter motor turns, but engine won't start |
Air in the fuel system |
Bleed |
| Fuel filter clogged |
Clean/replace |
| Fuel not supplied |
Turn fuel filter tap to "ON" |
| Internal engine fault |
Dealer |
Iseki GEAS AT23-AT33 engine while driving
| Symptom |
Possible cause |
Solution |
| Irregular idling/running |
Air in fuel system |
Bleed |
| Fuel filter clogged |
Clean/replace |
| Injector clogged/fuel leak/injection pump faulty |
Dealer |
| Fuel pump faulty |
Check/replace fuse |
| Engine stalls at lower RPM |
Injection pump faulty, valve clearance incorrect, injector faulty |
Dealer |
| Engine runs at too high RPM (racing) |
Governor contaminated, oil rising |
Dealer |
| Engine suddenly stalls |
Fuel shortage |
Refill and bleed |
| Engine oil shortage |
Refill |
| Injector faulty/engine seized |
Dealer |
| Overheating |
Coolant shortage |
Refill |
| Fan belt loose/damaged |
Adjust/replace |
| Radiator clogged |
Clean |
| Engine oil shortage |
Check/refill |
| White exhaust smoke |
Air filter clogged |
Clean element |
| Too much engine oil |
Check oil level and correct |
| Insufficient fuel supply |
Dealer |
| Black exhaust smoke |
Too much fuel supplied or injector pressure too low |
Dealer |
Iseki GEAS AT23-AT33 clutch
| Symptom |
Possible cause |
Solution |
| Clutch slipping |
Pedal clearance incorrect |
Adjust |
|
Clutch worn/seized |
Dealer |
| Clutch doesn't disengage fully |
Pedal clearance incorrect |
Adjust |
|
Clutch corroded |
Dealer |
Iseki GEAS AT23-AT33 brake
| Symptom |
Possible cause |
Solution |
| Poor or uneven left/right braking |
Pedal clearance incorrect |
Adjust |
| Brake worn/seized |
Dealer |
| Uneven pedal travel left/right |
Adjust pedal travel |
| Brake pedal returns poorly |
Return spring faulty |
Dealer |
| Pivot point corroded |
Remove rust and lubricate |
Iseki GEAS AT23-AT33 steering
| Symptom |
Possible cause |
Solution |
| Steering heavy or pulls to one side |
Steering shaft incorrectly adjusted |
Dealer |
| Toe-in adjustment incorrect |
Dealer |
| Tire pressure incorrect |
Bring to correct pressure |
| Play in ball joint |
Dealer |
| Too much play in the steering wheel |
Steering shaft worn or play in ball joint |
Dealer |
Iseki GEAS AT23-AT33 AT-shift transmission
| Symptom |
Possible cause |
Solution |
| Doesn't drive forward or reverse |
Lever not set to neutral before starting |
Set lever back to neutral and restart |
| Fuse blown |
Replace fuse |
| Hydraulic system faulty |
Dealer |
| Electrical/sensor fault |
Dealer |
| Can't shift |
Fuse blown |
Replace |
| Hydraulic system faulty |
Dealer |
| Electrical/sensor fault |
Dealer |
Iseki GEAS AT23-AT33 Superfullturn
| Symptom |
Possible cause |
Solution |
| Doesn't work |
Single-dial work selector switch still set to "Driving (Loader)" or "4WD" |
Set the switch to "Superfullturn", "Autolift" or "Tilling" |
|
Controller, hydraulic or sensor fault |
Dealer |
| Works unevenly left/right |
Sensor incorrectly adjusted |
Dealer |
From practice: known points of attention
On the AT27, owners report a specific phenomenon during plowing work: the 2WD/4WD indicator lights flash alternately and the dual-speed turning function (Superfullturn) temporarily switches off when lifting the rotor coulter; after moving the rotor coulter, the function recovers. The suspected cause is poor contact in the 2WD/4WD/Superfullturn selector switch or the associated wiring. This is not listed in the official troubleshooting table, but has been reported for this specific model — so if in doubt, check the wiring and switch first before replacing a more expensive component.
With grey imports, also keep in mind that official Iseki dealer parts and warranty are usually not available, and that hour meters on imported machines may sometimes have been rolled back or replaced. So with an unexplained fault, always check the basics first — wiring, ground points, fuses — before assuming a more serious defect.
Has your tractor been sitting idle for a long time or run on old diesel? Then sticking injector needles is a known problem with this engine family. Using a Diesel Injector Cleaner (SKU-60003) preventively can dissolve tar and carbon deposits and postpone an expensive injector overhaul.
💡 Shop4trac tip: Not sure about the condition of your injectors after a long standstill or irregular running? Adding a
Diesel Injector Cleaner (SKU-60003) to the tank is an inexpensive first step before resorting to a more expensive injector overhaul.
