Aloha,
My KX040-4 purchased new in 2019 just hit 1500 hours. Made the mistake of running it too slow, got code 29, limp mode, tech came out ($200/hr), did another regen, reset code, was ok for awhile but regen every 2-3 hours, then went back into derate. I took apart the DPF, soaked it in a DPF cleaner, put it all back together and it worked off and on for awhile. Also used some DPF cleaner gas addictive. Tech came out again, suggested I get a new oxygen sensor, no change. Recently cleaned off the 3 knock sensors with the same DPF cleaner and used a scotchbrite pad as advised by a mechanic. Still got code 29 and some times 21 too.
Even with crowfoot or special 6 point wrench heads (14mm), they slipped off, so had to use a pipe wrench to get the sensor nuts loose, use anti seize compound after. Should have used extensions to take out the whole DPF assembly, would have been easier to take apart. Runs fine, been at least six hours since regen, the inhibit switch and the one next to it don't work, hoping it will do a regen soon, so have been running it to clear resulting overgrowth, so it runs at 2300 but dips down to around 800, hope I am not doing too much harm. Cannot see any connection issues. Have yet to learn how to verify electrical continuity. Worried about breaking connectors while trying to disconnect. Perhaps somebody has had a similar situation?
Have also seen online diagnostic gadgets which say it can remove codes, yet contacted one who would not guarantee it would do so. Unless I hear of someone who has actually used one successfully, I will assume it's useless. Seems the codes go away by themselves. Removing fuses does not remove the code
Was thinking about doing a DPF delete, will do a different post for that.
My KX040-4 purchased new in 2019 just hit 1500 hours. Made the mistake of running it too slow, got code 29, limp mode, tech came out ($200/hr), did another regen, reset code, was ok for awhile but regen every 2-3 hours, then went back into derate. I took apart the DPF, soaked it in a DPF cleaner, put it all back together and it worked off and on for awhile. Also used some DPF cleaner gas addictive. Tech came out again, suggested I get a new oxygen sensor, no change. Recently cleaned off the 3 knock sensors with the same DPF cleaner and used a scotchbrite pad as advised by a mechanic. Still got code 29 and some times 21 too.
Even with crowfoot or special 6 point wrench heads (14mm), they slipped off, so had to use a pipe wrench to get the sensor nuts loose, use anti seize compound after. Should have used extensions to take out the whole DPF assembly, would have been easier to take apart. Runs fine, been at least six hours since regen, the inhibit switch and the one next to it don't work, hoping it will do a regen soon, so have been running it to clear resulting overgrowth, so it runs at 2300 but dips down to around 800, hope I am not doing too much harm. Cannot see any connection issues. Have yet to learn how to verify electrical continuity. Worried about breaking connectors while trying to disconnect. Perhaps somebody has had a similar situation?
Have also seen online diagnostic gadgets which say it can remove codes, yet contacted one who would not guarantee it would do so. Unless I hear of someone who has actually used one successfully, I will assume it's useless. Seems the codes go away by themselves. Removing fuses does not remove the code
Was thinking about doing a DPF delete, will do a different post for that.
Last edited: