Kohler Generator Fault Code List (Troubleshooting Manual)
Not all fault codes list come with a numerical listing. Some may just be abbreviated words from the actual problem. This can slow things down somewhat when you are trying to find out what is wrong with your Kohler generator in the middle of the night.
The code list can be found in the manual which is on our go-to manual website. The two choices you get are either a warning or a shutdown.
To learn about these fault codes, just continue to read our article. It has the codes and extra information so you know what is wrong with your Kohler generator. In this case, there are no numbers to make finding the codes easier.
Kohler Generator Fault Codes
Kohler Generator Fault Code List
| Code | Warning/ shutdown | Condition | Check |
| AC Sens Loss | W (1 sec.) SD (3 sec.) | AC sensing lost. In Auto mode, generator output AC sensing is lost. Detection begins 10 seconds after crank disconnect | Contact an authorized distributor/dealer for service |
| Accy PwrOver W Warning | W | Accessory Power Overload. An over current fault (short circuit) on the accessory controller power output | Contact an authorized distributor/dealer for service |
| Alt Protect | SD | High generator current has been detected. The generator set shuts down to protect the alternator from damage caused by overheating the windings (10RESV and 12RESV only) | Reduce the load |
| ATS ComError | W | ATS communication error. Warning is displayed if ATS interface connection is lost. See Section 2.5.3 | Check communication wiring between transfer switch interface board and generator set |
| ATS PhaseRot | W | ATS phase rotation mismatch. Transfer switch phase rotation does not match, ATS will not transfer. | Correct the ATS connection. Refer to the ATS Installation manual, wiring diagrams, and labels on the transfer switch |
| Aux Input | SD | Auxiliary input. An optional customer-connected input is closed. (Digital input from optional PIM.) | Check customer-supplied equipment |
| Batt Chg Flt | W | Battery charger fault. Input to PIM from an external battery charger (not the built-in battery charger) | Check external battery charger |
| Battery High | W | Engine starting battery voltage rises above 16 VDC for more than 10 seconds. Inhibited during the engine crank cycle. Clears when the battery voltage returns to an acceptable level | Check the battery rating and condition. Check the battery charger operation. |
| Battery Low | W | Engine starting battery voltage falls below 12.5 VDC for more than 90 seconds when the engine is not running. Not operative during the engine crank cycle. Clears when the battery voltage returns to an acceptable level | Check the battery rating and condition. Check the battery charger operation. Charge or replace the battery |
| Battery CrLo Warning | W | Engine starting battery voltage falls below 11 Volts for more than 10 seconds. Inhibited during the engine crank cycle. Clears when the battery voltage returns to an acceptable level. | Check the battery rating and condition. Check the battery charger operation. Charge or replace the battery |
| Eng Speed High | SD | Engine speed exceeds 115% of the normal running speed for more than 0.3 seconds. | Contact an authorized distributor/dealer for service |
| Eng Speed Low | SD | Engine speed drops below 85% of the normal running speed for more than 3 seconds | Reduce the load. Contact an authorized distributor/dealer for service. |
| Exer Not Sch | W | Exercise not scheduled. No exercise is scheduled on the controller. | See Section 3.6 or 4.5 for instructions to set the exerciser |
| Frequency High | SD | Governed frequency exceeds 110% of the system's frequency setpoint for more than 10 seconds. Function becomes active 10 seconds after engine start (10 second inhibit) | Contact an authorized distributor/dealer for service |
| Frequency Low | SD | Governed 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. Function becomes active 10 seconds after engine start (10 second inhibit). | Reduce the load and restart the generator set. Contact an authorized distributor/dealer for service |
| Lo Crank Vlt | W | Low cranking voltage. Battery voltage falls below 8 VDC for more than 6 seconds while the starter is engaged. | Charge or replace the battery |
| MainPwrOverL | SD | Main power overload. An over current fault on the 70 controller power output (short circuit) | Contact an authorized distributor/dealer for service. Check for shorted run relay. Check wiring for short circuits |
| Not in Auto | W | The 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 Low | SD | The LOP switch indicates low oil pressure for more than 5 seconds. Function becomes active 30 seconds after crank disconnect (30 second inhibit). Note: The low oil pressure shutdown does not protect against low oil level. Check the engine oil level regularly as recommended in Section 5 | 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 Crank | SD | Three unsuccessful starting attempts | Check the fuel supply, spark plug, and battery. Reset the thermostat. Check for loose connections. Contact an authorized distributor/dealer for service |
| Spd Sens Flt | SD | Engine speed sensor has failed or engine stalled | Contact an authorized distributor/dealer for service |
| Total Power High | SD | Measured load is greater than 102% of the generator set power rating for more than 1 minute (10RESV and 12RESV only). | Reduce the load |
| Volts L1-L2 High | SD | Generator 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-L2 Low | SD | Generator 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. Contact an authorized distributor/dealer for service. |
Some of the shutdown options will see an engine cool down running before the device shuts off.
Kohler UU Fault Code
Some of the fault codes for this brand of generator will be listed right on the unit. The UU code is just one of those and it stands for under voltage. This fault occurs when the voltage falls below 80% for more than 10 seconds.
This code will trigger a shutdown once it detects a low AC output. When it happens you will see that UU fault code. But the controller is not done as it will also display the following issues- engine runtime, crank cycle status, high engine temperature, over the crank issue, fuel pump relay, and low oil pressure.
Everything has to be reset and fixed before the generator will begin to function again. You may have to reboot the controller and those instructions are in the manual we will link to later.
What Does a Locked Rotor Mean On a Kohler Generator?
The sources and repairs may depend on the model of the Kohler generator you own. For the RESA model, it may be that the controller is bad. There may be 3 controllers on this model but the technician was not clear.
Then the RESV model does not use the mag pick up sensor for engine rotation feedback like the older generators once did. For some reason, the controller on the RESV gets its feedback on the back end.
It is a different system and when you get the locked rotor error message, then it could be the battery that is the problem. The battery is dead and needs to be recharged or replaced. At least this is the source for 90% of the time.
The other 10% usually ends up being a bad controller and it will need to be replaced. Other possible sources could be a damaged rotor or a problem with the wiring. Updating the firmware for the controller may help solve the problem.
Download Kohler Marine Generator Troubleshooting Manual
You know our go-to website and it is already linked above. That link will take you to the standard troubleshooting manual for the Kohler 8RESV unit. This link will take you to the 5E service manual just in case that is the unit you own.
You can search that website for the Marine version and it is probably there. But for faster service, go to Kohler directly. They have set up a great manual download page and you just have to find the right one.
This page has a search function requiring a model number and model identification but you can also scroll down and try to find it on your own. The best place to go for manuals is the manufacturer. You can ask questions directly if you do.
Kohler 5E Manual Pdf
We jumped ahead of ourselves and listed the 5E’s service manual already. That is because it came up in our search for the Marine generator manuals. You can use the same manual locator page in the last section to find both the service and regular owner’s manual for the 5E.
Or you can go to this discussion forum and get the parts, service, and installation manual for the 5E. when you know the right discussion forums to go to, you can find a lot of useful information.
However, there are not that many websites offering any of the 5E manuals for downloads or in PDF formats. You may have to do a little extra searching when you get the time to track down more options. We did not find that many and most were linked directly to Kohler.
This is to be expected when a company does a great job in making its manuals accessible, there is no need for secondary websites to do anything.
How do I Clear The Error Code On My Kohler Generator?
These instructions are for the 8RESV and you need to make sure the problem is fixed before trying to clear the code. The instructions are found on page 24 of the manual at the first link above:
RDC2 Controller
Press the OFF button to reset the controller, or follow the procedure below. See Figure 2-2.
1. While the fault message is displayed, press the Select the button to go to the Overview menu.
2. Press Select again. The active fault message is displayed.
3. Press Select. Confirm Clear Fault: NO is displayed.
4. Press the Down arrow button. Confirm Clear Fault:
YES is displayed.
5. Press the Select button to enter YES and clear the fault.
6. Press the Select button to return to the overview menu. The controller changes to OFF mode.
7. Press AUTO to put the generator set into automatic mode.
DC2 Controller
Press the OFF button to clear the fault message on the controller
Kohler 7.3 Marine Generator Troubleshooting
The manual has several different sections that contain troubleshooting help for selected parts. The first section deals with the fuel system including the carb. Those are on pages 24 and 25.
The controller troubleshooting begins on page 33 and goes to page 34. Then the generator troubleshooting information begins on page 39. That should provide you with all the information you need to fix your generator.
However, the manual may not cover everything as some of the error codes above have said for you to contact a Kohler dealer and not fix it yourself. Their website has a find a dealer locator system.
What is nice about their system is that they divide the dealers into 3 categories-- expert, dealer, and distributor so you know what you are getting when you contact them.
Some Final Words
Knowing the fault codes and what they mean is only half the battle. The other half is knowing if you can DIY the repair or need to go to a dealer and let them do it. As for parts, you may find those at different locations around your area.
Or you can use the Kohler website and look under their parts & service category at the top of the page to get what you need. They prefer that you use genuine Kohler parts.
