Doosan G25P-5:
doosan g25p-3 no throttle at start up,code 29

I have a doosan g25p-3 that will not have any throttle response at start up. Code 29 comes up which is a driver fault to the throttle control unit. I have ohmed the wires from the secm to the throttle control unit. I have ohmed the wires from the pedel throttle position sensor to the secm. This driver fault would be the 5v reference signal that is coming out of the secm from the information that I am seeing. There is also a second control box on this unit under the dash that ties in with the throttle control. I have checked over the harness for rub through damage. Today however I checked for a battery constant (keep alive) power wire to the secm and did not find any. The no throttle will happen from 30 seconds after start up to as long as 5 minutes. Turning the unit off several times and restarting it will usually work after many attempts. I did get a new secm and the unit has a new throttle control unit on it. Does anyone have any good schematics for this or can they tell me which pin/wire color going into the secm should be a constant 12v keep alive power. I am thinking that this power is missing as this only happens when the lift has been sitting for a long period of time. Im thinking the internal battery in the secm drains down and the secm has to reset itself on that first start up. Any help or insight would be appreciated.
  • Posted 8 Mar 2018 16:25
  • Discussion started by al_h
  • Wisconsin, United States
Showing items 1 - 2 of 2 results.
Thanks, I had done the wiggle test and tested each sensor. I tested the amp output from the SECM to the electronic throttle body and it fell way below the 5amp maximum. What I actually found today was that even though this unit would run perfect and start right up, the main coil wire would arc at startup and was sending voltage acrossed the block which should have been dissipated by the block to battery ground wire. However it seemed to travel through the o2 sensor and back to the SECM causing it to throw code 29, but only when everything was cold from sitting. I could unplug the 02 sensor at start up and it wouldn't error out with a false driver error. I got frustrated thinking it was gonna turn out to be something stupid and unrelated and sprayed the wires while it was running and discovered the arc on the coil. This was crazy and I will probably never see it again. The engine ground was pretty clean, but I cleaned it up some more. The engine also had some oil/dirt mix from a leaky valve cover that I believe contributed to some of this issue helping the stray voltage. The only thing I can come up with is when this engine got warm or hot the resistance went up and the voltage did not pass accrossed the block. Crazy, just crazy.
  • Posted 16 Mar 2018 14:51
  • Modified 16 Mar 2018 14:55 by poster
  • Reply by al_h
  • Wisconsin, United States
Doosans frequently have wiring issues, the plug and wiring connecting to the electronic throttle body often will break. The breaks sometimes occur inside the vinyl wire coverings. A wiggle test while running may produce throttle function. Doosan has a kit to repair or the local electronics store can source the parts.
Another source of wiring faults is located where the harness runs over the transmission to the SECM.
Contact my profile i may have other info. Serial number please
  • Posted 12 Mar 2018 02:04
  • Reply by tom_p
  • Alberta, Canada

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