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Author Topic: Woodmizer LT40 28 Kohler how to reset ECU  (Read 911 times)

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Offline jovol

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Woodmizer LT40 28 Kohler how to reset ECU
« on: February 09, 2019, 12:43:10 PM »
I replaced the O2 sensor on my 28HP Kohler Command, and I started adjusting the idle RPM since they were very low. Now, the engine RPMS oscillate over a period of like 10-15 seconds. I think I need to reset the ECU and do the "TPS learn procedure". The Kohler service manual has directions on shorting two wires together, turning the key on-off for 10 sec, and that should reset the ECU, but the wiring diagrams don't match up to my Bosch ECU, so I don't know which wires to short together. Anyone successfully done this before? 

Thanks, John
2017 LT50 wide, 2004 LT40 G28 (for sale), ms250, ms661 42” granberg, Logrite fetching arch, 2000 New Holland LS180, Ford 6.0s

Offline Ben Cut-wright

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Re: Woodmizer LT40 28 Kohler how to reset ECU
« Reply #1 on: February 10, 2019, 10:18:22 PM »
Not sure what you mean by "wiring diagrams don't match up"?  Why did you replace the O2 sensor?

These instructions are in the manual for that engine.


1.  Connect (jumper) white wire to black wire in four way diagnostic port.
2. Turn key on, then off for ten seconds.
3. Turn key on, then off for ten seconds a second time.

TPS learn:

1. Turn idle screw clockwise one full turn prior to key ON after ECU Reset.

2. Start engine, run at low idle until engine is warm.

3. Idle speed must be above 1500 RPM. If below 1500 RPM, turn idle screw up to 1700 RPM and then shut down engine and perform ECU Reset again.

4. Adjust idle speed down to 1500 RPM. Allow engine to dwell at 1500 RPM for about 3 seconds.

5. After this, adjust idle speed to final specified speed setting.

6. Turn key OFF for 10 seconds.

Offline MartyParsons

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Re: Woodmizer LT40 28 Kohler how to reset ECU
« Reply #2 on: February 11, 2019, 05:12:55 PM »
I was going to look this up and take it out of the book. Ben has it done. 

I would check the TPS and the throttle plates make sure the screws on the plates are not loose. 

“A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty.” -Winston Churchill

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