Fuel Gauge And/or Range Readout Intermittently Malfunction

[IanShere]

We have an 04 GX-470. Most of the time the fuel gauge and the range readout work OK. However, sometimes, the fuel gauge works, but the range shows 0 miles, or they both don't work - fuel gauge shows empty and range = 0. My wife says she thinks she's seen the gauge = empty but the range still showing xxx miles - I haven't seen that.

We've been to 2 different Lexus dealers, paid for diagnostics at both and gotten no fix. In fact, they have both said they can't find anything wrong. But thanks for your money......

To my way of thinking, these would both get their initial information from the same source - some sort of sender unit on the fuel tank. However, as both gauges do not always go out together, I'm inclined to think that this probably isn't the cause. I would think that the range readout comes from some calculations done by the onboard computer.

Anyone else experienced this? Is VERY frustrating as we regularly drive from Phoenix to Sacramento.

[Zevman]

Our 2004 GX470 has similar gauge issues. For us it's the fuel and temperature gauge. Sometimes the digital fuel gauge is in concert with the analog, and sometimes not. Seems like somewhere there is an electrical fault or the onboard computer is acting up.

Wish I could help you, and help myself at the same time! :--(

[Zevman]

Actually the directions found here gave me the confidence to remove the entire assemble http://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/488077-fuel-gauge-fix-tutorial-93-94-a.html. The directions were not identical to my GX470 2004, albeit it was close enough to get the job done without breaking anything.

Once the gauge assembly was carefully removed, I unscrewed the back cover to observe the circuit board. The capacitors looked good. Nothing was swelling nor leaking. So I decided instead to screw back the cover, and clean the contacts (male & female) ends using PURE Electronics Contact Cleaner, http://www.amazon.com/CRC-5103-Quick-Electronic-Cleaner/dp/B000BXOGNI. Something you can find online, Radio Shack, or Fry’s Electronics for $4.50 (It’s basically 70% isopropyl alcohol in a spray can). The contacts I’m referred to are the ones that connect the assembly to the car harness.

Once sprayed, and carefully dried everything was reassembled and the temperature and fuel gauge magically worked.

For all the fuss, I would consider this a tremendously simple job that cost about 1 hours’ time.

Not a clue what the dealer would charge, but I’m certain this would not be cheap. Happy for now to report that

job is complete with gauges working correctly. If the status changes, I will keep everyone posted.