2010 RX350 check AWD system

A while ago my “check awd system” light on my 2010 Lexus RX350 illuminated. The car has been well maintained and I rarely drive it (maybe 10 miles a week). It still seems to drive the same, but the light is on. I thought it was linked to the gas cap, because it seemed to appear out of nowhere and will turn off occasionally. I recently purchased a new gas cap, but the light hasn’t turned off (I haven’t been able to find a correlation when the light turns on and off). Our driveway (where the car is parked) is on an incline.

If the gas cap was the culprit, the Check Engine Light (CEL) would have lit up.
This is also almost surely not related to parking on an incline, and the fact that you rarely drive the vehicle has nothing to do with a possible AWD system problem.

Because the AWD warning light portends potentially pricey repairs to the AWD system, I strongly suggest that you have a qualified mechanic inspect the vehicle a.s.a.p.

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Have you replaced the tires? If so, are they the same exact size on front and back? Different sized tires often lead to AWD problems. We can’t trouble your system with the usual diagnostic tools that a repair shop can. You should take it in for an evaluation. If you have a relationship with a shop already, take it there.

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The code c1298- linear solenoid. We took it in and the shop said that they tested the power supply for 4wd ecu and it was fine. They checked tested the wires from the ecu to the solenoid sensor and it was fine too. And they checked the connectors and they were fine too. They didn’t really know what else to do. I guess it’s time to go to the dealership.

The tires were all replaced last year, a while before the light came on. I am not sure the sizes, but I would assume they are all the same (I can check in a bit). Last time I took it in they said they should be rotated and balanced as there is some abnormal wear, although the tread is good.

Did you follow their advice at that time?
Have you consistently rotated the tires as specified by the mfr? (I think that this is supposed to be done every 5k miles, but it is possible that the mileage interval is a bit longer on this model.)

In any event, uneven tire wear on an AWD vehicle can cause damage to the drive system.

I didn’t that time (because it hadn’t been even 3k since the tires were replaced), but I do get them rotated and balanced per manufacturers specs or sooner if the wear signals that it is needed. I was planning on taking it in and getting it done with the light came on. Would it be worth it to get it done now, before going to the dealership?

Next step is to measure the resistance of the solenoid. If the power supply, wiring and solenoid are good, the ECU has failed.

Tire condition has nothing to do with this, there is an open or shorted circuit in the rear differential AWD coupling solenoid. This means that the AWD lock feature won’t function when you push the button on the center console so stay out of the mud.

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Thanks @Nevada_545 . Is this something I can do, if so how? Or is it best to bring it into a shop. Do you have an estimate of how much this repair would cost? Also, as long as I don’t need my awd lock button (I am pretty sure I have ever used it) is it ok to drive the car occasionally or should I get it fixed asap?