Hi, I have a 2015 Lexus NX200t with 71000 miles on it. SO, last month in August, I had for the FIRST TIME Reduced Engine Power show on my screen. Called the dealer, got a code of P125D71, was told it was possibly bad gas, or something on one of the sensors. So they reset/flashed the system to clear it out and hoped it didn't come back on. Well, fast forward to a week later, same message again for a 2ND TIME. This time they changed the sub-tank on the fuel actuator. Got my car back on 8/29/2019.. WELL, fast forward to this week, yesterday, 9/9/2019, it came on again for a 3RD TIME! Now my question is what else could it be! I've read the service bulletin on this previous code, P125D71 and it talks about the sub-tank, replacing it, & replacing other little components. SO What else could this be? I've read on other sites that state something about the transmission, MAF sensor, & air filters (which are clean). What else could this be? I'm still waiting on my local dealer to call me (I say it a ripe off to go a dealership because they always want to get more out of you then needed). So do anyone have any suggestions? My car was running fine. That was no limp mode on this car at any time - we never felt the engine lose power. We were upwards of 80 mph to get to the dealership. We use and always have used premium gas. We don't take it down dirt roads or drive crazy (we have two kids). So we haven't done anything to this car.

 

usually a dirty fuel filter....but with computers running cars these days who knows.

 

You would think that they replaced that when they replaced the sub-tank or I could be wrong. I'm not like most women who don't know much about cars. My dad and uncles were mechanic when I was growing up so I'm pretty smart on what's up with my car.

 

As found online, MIL "ON" P125D71 – Fuel Flow Control Valve Stuck
https://testing-public.carmd.com/Tsb...1/L-SB-0017-16

I'd say you need to verify from your NX VIN number if this TSB is applicable, vehicles manufactured before the reference VIN #JTJBARBZ#G2079953 (AWD/F-Sport) or JTJYARBZ#G2039757 (FF/F-Sport)
If true,I'd print a copy of this TSB and verify if the dealer service confirmed they have done this repair, as opposed to blaming it on bad gas! If this dealer refuses, try another one as you do have a case, and bring this up to the higher level attention if need be!

I download this TSB anyway just in case it disappears to never never land
Edited to add: as I realized your mileage is over that (48 months or) 50K miles, they may impose a service charge?

 

Yeah, the first time we took it, it was 69K and Lexus agreed to pay for part of the service. My VIN starts off at #JTJYARBZ.... when we took it the first time, it did show the code listed on the MIL "ON" P12D71 because I saw it next to my paperwork when I got it back the first time. I just got off the phone with my husband and he said they are taking my the fuel tank and everything they assembled off. Making sure everything is the way it was suppose to be. They just called and said one of my "O" rings has a crimp in it and that could be causing the problem. So we will see...

 

Thanks for your feedback on how the dealer worked on this issue and a possible cause of this problem! I suppose your VIN ending digits must have been "smaller than" the reference "2039757", as the starting alpha letters are the same. It's good to know the possible cause, or in your case perhaps it is the O-ring was (accidentally) crimped, which would have cause the malfunction after 69K miles mileage. As for my NX (AWD) my VIN is smaller than that reference 2079953, thus it may be subjected to a similar issue, possibly due to their manufacturing/assembly process. But of course not all NXs have this (presumably just the O-ring) problem. I'll keep my finger crossed

 

OH, I'm definitely keeping my figures crossed....

 

my dad had this happen on his 18 f250 truck and it was caused by fuel additives (the ones you add every tank fillup). it was 2 grand to fix and ford even did a test on the sludge that built up in tank/valves/filters to prove it was aftermarket additive. so my pops filed claim with car insurance and said someone put **** in his gas tank and insurance paid.

 

Wow... that's crazy... I can say that my husband and I haven't put any additives in my car. I don't like doing that.. However, I did do that to my 04 Honda Accord with the one that helps with build up on the injectors and valves. It worked like a dream. Sold that car with 294,000 on it this past spring. That car was the best thing ever!!!!!!

 

My 2016 NX200T water pump failed @ 75,000 and dealer service dept. says my fuel injectors also needed replacement. after discussing with corporate Lexus and dealership, they will cover the parts for fuel injectors only. My car was regularly maintained by the dealership hence why I was disappointed. Soon after, i see the 'reduced engine light' and a noticeable loss of power with Whipple hissing sound from acceleration, so I brought in the car 9,000 miles since the fix and NOW the dealer is saying turbo failure.. Unreal Toyota, I guess new engines aren't reliable and made to last 100,000 anymore. Set to discuss with corporate Lexus and dealership again next week about this problem and I surely won't be investing any more in this garbage. I guess this junk is drivable without turbo but for how long before I jump ship is the question.

 

We have my in-laws 2016 NX200T in our garage and it has sat for about 3 months without being started or driven (in-laws are in the Philippines). We're usually good about starting and driving it every 2 weeks but it's been kind of busy here. I went yesterday to start it and battery was dead (which I could understand from sitting so long). Charged it overnight, and when I pressed the push start, lights blink like crazy and a fast clicking sound comes from the engine compartment. Then 2 messages pop up, the 1) reduced engine power/see your dealer and 2) Parking Brake Unavailable.

I'm not too familiar with a Lexus so I'm hoping someone can shed some light. Prior to this when we were able to drive the car, it was driving perfectly with no issues. Thanks in advance.

 

Scotty Kilmer (youtube channel) is right again, he said try to avoid turbo engines. Lexus/Toyota are generally pretty reliable. ES350, GS350 and probably RX350 are very reliable. LS500 I think isn't listed as reliable on Consumer Reports.

Water and fuel pump are generally weakness for Lexus/Toyota vehicles.

 

I'm not an expert on the NX but reading the other forums, it sounds like the battery drained causing the computer to fall into a weird state. Check the voltage on the battery to see if it's normal with a voltage meter. Autozone maybe able to that for free.

If you choose to change the battery yourself:

Turn off the vehicle and wait 30 minutes before disconnecting the battery terminals for the computer to shutdown. Then wait another 30 mins, connect the battery terminals back (even with new battery). Let us know if it works if you attempt it.

 

Thank you. I have it on a slow deep-cycle charge and it seems to be charging more steadily. I found a way to hook the positive cable directly to the battery without it slipping off (as oppose to connecting to the bracket). Once it's fully charged in the morning I'll give it a start. If it doesn't work, then I'll try your suggestion to do the "30min, disconnect, 30min, reconnect." Thanks!

 

If you have a voltmeter, check the voltage before you try to start it. If it does not start, check the voltage again. A battery sitting dead for a while can kill the battery.