Our Dmax goes into limp mode from the camper trailer

After spending nearly 9 weeks on the road with our Isuzu Dmax and the Soft Floor Camper Trailer, we’d become fairly familiar with how things ran and were having a decent run (minus the two insurance claims with Club 4×4!).

The first real issue we had with the Dmax happened in Karratha when we called in to get some 2 stroke oil for our little tinny.

EDIT – If you are chasing real world feedback on the Dmax, we’ve done a 4 year review which covers everything from good to terrible. You can read it here – Isuzu Dmax 3 year review. If you are specifically interested in where they fall short, check this out – Where does the Isuzu Dmax fall short?.

Gravel driving
3 months on the road with the Dmax

After grabbing the oil, I jumped back into the Dmax, and went to move the gear shifter from Park to Drive, as I would normally and to my surprise, the gear lever wouldn’t move, no matter what you did. I messed around for a while, wondering if it had mechanically jammed, until I noticed the little shift lock button to the side of the lever.

The shift lock was engaged, and only by pressing the button down would it move into gear. Up until then, I’d always wondered what the purpose of that button was! I took off, a bit unsure of what was going on, and knowing we had 500km to drive that day it had me a bit concerned.

Not long after, I realised I couldn’t manually change gears either via tiptronic, and it wouldn’t recognise whether it was in reverse, drive or neutral on the dash like it would normally. After dropping Sarah off at the shops to stock up with food for the rest of our trip, I pulled into a service station and found the orange check engine light on. Exactly what I wanted, with a big drive ahead of us!

After fuelling up, I pulled off the road, and checked the error codes on the Ultra Gauge. PO707 and P0708. Of course, the massive chunk of paperwork I took with me didn’t have what those Isuzu Dmax fault codes were, so I moved onto Google and Facebook for more information.

Ultra Gauge in the Dmax
The Ultra Gauge is fantastic for reading error codes and monitoring our vehicle in real time

Everything pointed to a problem with the brakes or reverse, and some further digging I found that the reverse lights on the camper trailer and car weren’t working.

Some further digging on the Dmax pages on Facebook made it obvious that a fuse had blown, and I spent a long time trying to find it. There are two fuse boxes in the Dmax, and I only knew of one!

Turns out the reverse lights fuse for Dmax’s is located behind the coin holder on the drivers side, and is labelled back light. It was a 15 amp fuse, blown and I didn’t have any to replace it, as they were the legless ones (later I found out you can install the bigger ones with the legs, and they just sit out further).

In the mean time, I’d rung Isuzu roadside assist, and RAC sent someone out about an hour later, who confirmed it was the trailer causing the issues, gave me a few fuses but couldn’t assist as technically it wasn’t related to the vehicle.

Dmax fault codes
Who’d have thought the trailer could blow the Dmax’s fuse?!

I rang Stephen, a great mobile auto electrician in Perth, who suggested disconnecting the reverse wiring for the camper trailer (trailers don’t legally need them, and often don’t come with them, which was news to me!), which I attempted to do, with no results.

Turns out I’d disconnected the wrong wiring as the previous owner had wired them up with the wrong colours. Great. Now, I will be the first to admit my 12V fault finding skills are not very good, but I gave it a crack anyway.

Eventually, I just drove to an auto electrician, who removed the reverse wiring from the trailer plug, and sealed it all back up again. A new fuse, clearing the codes with the Ultra gauge and all was back to normal.

Trailer wiring faults

I see this exact issue pop up online on a fairly regular basis now; someone tows a trailer and then has it stuck in park, and capped at 80km/h along with the usual limp mode symptoms. I guess somewhere along the wiring from the camper trailer plug to the lights there’s damage, and its enough to pop fuses in the Dmax. 

Sometimes its the reverse fuse, or the back light fuse, but each time it relates to damage within the trailer wiring itself.

Ironically, our camper trailer has done thousands of kilometres of rough roads, and the straw that broke the camels back was coming out of Cleaverville that morning, which is a pretty decent gravel road. Our 3 month trip up north had a few things that didn’t go to plan, but you have to expect things to go wrong; it never runs completely perfectly! 

Dmax trailer wiring fault
Of all the places it could have failed, it was right near Karratha and an auto electrician

Nanutarra it is

After getting a feed and filling the water tanks, it was 2:30PM and our 500km drive just wasn’t going to happen. We drove a few hundred km and stayed at Nanutarra Roadhouse, which was actually really good.

Modern cars have so many electronics that are interlinked and sensitive that its easy to cause issues. I said to Sarah had this have been the 80 series Land Cruiser I wouldn’t have known anything was wrong until someone pointed out I had no reverse lights. How things have changed!

We literally lost the alternator on the 80 heading to Manjimup one day, and drove several hundred kilometres without it, including a number of stops and then swapped it out that night, at camp! Still, that’s the way technology goes, eh?!

Asides from the Dmax turbo failure and the leaking transfer case seals, we’ve had a fairly uneventful ownership so far, and I’m still happy we sold the 80 series Land Cruiser for a Dmax.

This blog is honest, and every problem we have with the Dmax is noted shared here!

See you out there!

80 Series Land Cruiser
Our previous Land Cruiser, which was very different

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  1. John payrits says:

    Hi thx for your news letter may I ask details of your auto electrician friend or call 0416322304 John
    I am in Perth and have a Dmax That I am setting up for touring.thx