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The dreaded limp-home mode


New member
Hello all - new Kia Sedona owner here. We bought a gently-used '09 in June, no accidents, no rust, very clean, one owner, clean CarProof, and just 94K km on the clock. I was sold by the very roomy, versatile, and well-thought-out interior.

We just took it on its first extended road trip, 3000+ km to the Canadian Rockies and back. Near the end of the 1st day, the Check Engine light came on, and the van lost power. I pulled over and checked the ScanGauge. The TPS stayed at 17%, ignoring throttle input, and the feedback status indicated Open Loop, typical of no input from the O2 sensor.

I figured the engine had gone into some sort of limp-home mode, and that maybe I could reboot it. Although I had a full complement of bike tools, and although I routinely carried tools in our previous very elderly van, I did not have a 10 mm wrench to loosen off the battery's negative terminal.

I cycled through several stop/starts, and after a few minutes the CE light cleared itself and the van ran fine. I bought a small adjustable wrench.

The van did it again a few days and several hundred km later, and I used the wrench to remove the negative terminal. This reset the CE light immediately. Yay!

Two days later, on the way home, it did it again. I had bought a 10 mm wrench earlier in the day, so was able to 'reboot' things very quickly. But this time it didn't work. I removed the ground several times until the CE light reset. I was now thinking that perhaps time off rather than the reboot was what helped.

On the way home, I noticed, at times, that the van seemed to be bucking slightly, with or without cruise engaged.

When we got home, I did the Google thing - it seems that this is a common problem with the Hyundai/Kia 3.8 Lambda engines, and that the TPS is typically to blame.

I like to buy locally, but none of the jobbers offer a TPS or throttle body ass'y, and the dealer wants C$660! Yikes!

I've found several on line, including Cardone and OEM. They are way cheaper than the dealer part.

1st Q: Is this likely a TPS/throttle body issue?

2nd Q: Is the Cardone part a good one, or am I better off going with the dealership part?

3rd Q: Does the ECU/PCM have to be re-flashed to be compatible w/ the new part, or will it learn on its own? I like to do my own wrenching, and would prefer not to have to take it in.

I'm hoping that if this is the problem it will cure the rather anaemic power output and high fuel consumption. (The van was drinking 11 - 12 litres/100 km @ 100 - 110 kph, more than I'd expected.) The one plug I pulled was slightly sooty, making me think it's been running a bit rich.

Thanks all in advance for your help!

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