RV goes into Limp Mode

by D. Horner (Ottawa, Canada)

Question: I have a 1992 Cobra Sonoma with a 4 cylinder Isuzu TURBO diesel . The Econo light comes on and flashes and the transmission gears down and goes into what they call limp mode. If you turn off the ignition it will reset and may not happen again for twenty minutes. My mechanic is stumped. He replaced a switch in the transmission but that wasn’t it. Has anyone ever had this issue ? Any suggestions?

Answer: We don’t have any input on this one, but are posting your question in the hope that someone with relevant experience or expertise will comment.

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Aug 08, 2013 Perhaps unrelated but I just fixed this same problem
by: Anonymous


I have a 1999 Trek (which is why I’m viewing this) and a 2008 Sprinter van. My Sprinter had this problem and it was caused by metal filings building up on the magnetic speed sensors inside the transmission, which caused a mismatch in transmission speed and wheel speed.

Just an FYI.


Sep 27, 2012 Limp mode
by: Doug H


Thanks everyone for your postings- Great news we found a wizard who made a drop resistor and we were able to go to Murtle on Thursday (only two days late). The machine runs perfect .


Sep 26, 2012 Isuzu Transmission
by: Dick K.


I experienced your problem for the first time last week in my 93 Safari Trek. I reset the computer by removing the transmission control module fuse for a few seconds and the problem hasn’t returned.

Since I suspected the transmission inhibitor (gear selector) switch, I exercised the switch by shifting through all the gears about 20 times with the engine not running. Old switches collect dirt etc. and a little use sometimes helps. The problem hasn’t happened again but I will disassemble the switch and clean it when I get home.

A friend sent me a copy of the brochure for the Sonoma by Cobra and we were discussing “who copied whom” in the design of the 24-foot, as they are almost identical.

Since there are quite a few Treks built on the same chassis you might check out the Trek Track’s group and the I-trek info letters site for information.

Hope this helps,
Dick K. 93 Safari Trek 2400


Sep 05, 2012 Might be an actuator
by: Sandra G.


I drive a semi-truck and when an actuator goes out, it cuts the power down so that the engine does not get damaged.