Clive-D

Hi - I have a 2008 RX400h, owned for just over a year. Best decision I ever made! I thought 10 years or 100,000 miles was the warranty on the battery but tbh the battery is rock solid. It's scare mongering. If there is a hybrid health check from Lexus, then you are fine. You can also use a specialist to repair individual cells should a problem occur, at a fraction of the price of a replacement battery. At 67k it is barely run in. Mine was 120k when I bought it and I've done 11k since without the car missing a beat. I paid £6,500, a couple of dings but good service history. Plugs change at 60k intervals so got that done (big job!) as it needed a service, the wheels are usually rubbish, mine was no different so got them refurbed properly (not painted) at £65 each, and had the bonnet front and two corners with deep scratches painted. Cam belt and water pump changed at 100k. So I got a £46k beast of a car for about £7200 and I have no regrets. I don't use Lexus as they are way too expensive for an older car, my local garage service a couple of others. Only issues I had were oxygen sensors with an electrical specialist sorted. I replaced the mass air plow sensor which probably didn't need doing as it turned out but I have the original still as a spare. The self levelling headlights don't work and is a common problem, my lights are a bit low but pass an MOT. Again, costly to replace but YouTube have videos on cleaning and replacing the springs which is usually the issue. The sensor site on the top of the rear axle on the drivers side and get full of cr*p. If your lucky they can be cleaned up. Dead easy to remove with the wheel off. I just have the front fogs on as well which is plenty for me I have had one of the four O2 sensors fail and the garage said don't get an OEM one (£60 or so) as they won't turn off the engine warning light so I had to bite the bullet and paid £193 for the Lexus one. If was smooth before it is even better now so worth the spend! So back to the battery. Toyota state the hybrid batteries in their cars are zero maintenance and are expected to last the life of the car, which is 18 years (I think). Search here for battery issues, very few. Everyone seems to worry about hybrid batteries. As a rule they are way more reliably than the engines they support! The pulling power and acceleration is breathtaking. On a journey I will sometimes turn off the music and sit in silence. Literally. No bumps, no creaks and squeaks, tiny bit of wind noise. It's surreal, feels more like flying than driving. I love it. Put 15 bags of gravel in the other day, say 30kg a bag, that's 450kg. Barely noticed it was there!! Buy it if the history is good, walk if no history. I went 200 miles to get mine. I had the car surveyed by Click Mechanic which I would highly recommend because as you say, these are very complex cars and can be expensive if they go wrong. The have a 3.3L V6 engine, it eats miles. Drive with a feather light right foot, lift of whenever you can, keep 70 and under on journeys, that way I get 34mpg in summer, 29/30mpg in winter cos the engine works the heater. Trick I do is use the heated seat instead of the heater as much as I can. Good luck!

Thanks Herbie, just what I wanted

Apologies if this has been covered previously, various searches didn't find anything. I have a 2008 RX400h and following some wiring damage (repaired by a specialist) I am left with a consistent code P0137 O2 Sensor Circuit Low Voltage Bank 1 Sensor 2. Sometimes also P0138, High Voltage, same sensor. I am getting this replaced by my local garage and they have asked if I can confirm where Bank1 Sensor 2 is located. I can find RX300 and RX450h diagrams, but not one for the 400h. I understand it is post cat, but is there more than one post cat? Cheers, and thanks in advance. Clive

Thanks for the advise - 'you get what you pay for' is a good rule generally. I'll ask my electrical fitter. I have had a problem resolved in another lengthy thread with all sorts of error codes being thrown up. Damaged wiring was found and replaced, this error is the only one that comes back, my chap said if it does it will need replacing. Hopefully this should sort it.

Hi all I've had an ongoing electrics issue which has been resolved but the legacy is I need to replace the Lambda sensor... The main code that comes up is P0138, O2 Sensor Circuit High Voltage Bank 1 Sensor 2. If I don't clear it for a day or so I also get P0137, same error but low voltage. My car is 2008 so I don't think I will have the car for 10 years... so my question is, with prices varying from £30 on eBay to £70-150 at Eurocarparts, has anyone had experience and recommendations. Cheers, Clive

So to close this topic, one error keeps coming back, P0138, O2 Sensor Circuit High Voltage Bank 1 Sensor 2. I was advised this would need replacing if it kept re-occuring, which it does, so I'm starting a new thread for advice on how much to spend on one as they vary from about £30 - £150.00. As the car is 10 years old I don't necessarily need one to last 10 years so long as it functions as it should. I'll share the link to the discussion. Cheers guys for all your help. Still managing almost 32 mpg average which is good in cold weather.

Hey sorry, missed this. (The sensor sits right on top of the engine at the back near the windscreen.) The connector has two tabs, one on top, one underneath which is a bit of a fiddle. If you squeeze on them and wiggle the connector up and down gently as you pull back it will disconnect quite easily. There are vids on You Tube. Good luck!

Good point (and BatchelorDays), but the error code P0137 is very consistent (Sensor circuit low voltage Bank 1 Sensor 2). If i wait to clear it I may also get P0138 (Sensor circuit high voltage Bank 1 Sensor 2). Always the same sensor. Worth asking if it's the same one with the damaged wiring. Pic attached.

It's the electrician's word for the OBD II reader! I'm not getting any other codes now, so I'd just get the same code doing what you suggest. I read it is best to replace both if you have an error on one bank - sensor 1 pre cat and sensor 2 post cat. The logic being that if sensor 2 has failed and is replaced, sensor 1 whilst it may still be working ok may not be in sync with the new sensor and throw up an error (think that was the gist of it). Anyone got experience of fitting these as the price variation is huge. With an older car I don't need one to last another 10 years, but equally don't want to create problems by fitting a cheap poor functioning one!

Latest update... ! I got a return of the error codes after a couple of days - O2 sensor circuit low/high voltage Bank 1 Sensor 2, codes P0137/138, then more - so I got the car back to the guy. He said there were loads of codes which he cleared. He did a long test run and said the can ran beautifully with no problems. Suggested I leave the dongle unplugged as they can throw error codes but if I keep getting O2 sensor error codes it's likely I'll need to replace it. The car is running fine but every 2nd or 3rd start up, the engine light will come on during a journey, always the same, which I stop and clear, then it's fine again for a while, so I going to replace the sensor. Anyone got any experience of replacing sensor 2 in Bank 1? I'm quite competent if it's accessible. Otherwise its back to the garage. What is an OEM part number? Thanks. Nearly got this sorted.

I don't think that was a problem - the engine kept running rough on tickover when I had the error codes. It is stopping as I would expect now, after the repairs. The battery was replaced March 2017 and hasn't been disconnected since. Surely the problem would have been there when I got an engineers report before I bought the car ? There's a lot of talk here about 12v battery issues, so it seems they can be problematic.

Thought about it - if the car's going fine why tempt fate! If the consumption stays down I'll try. The guy reckons the old sensor was probably ok. I'll put it in the spares dept 😉

Got the car back today. 3 hours labour, no parts required. He found error codes relating to the MAF sensor and all 02 sensors (same as me). He found a blown fuse and replaced it, cleared the codes and test drove. Fault returned but fuse not blown. Scan found fault on 02 sensor 2, band 1. On the ramp he found damage to the wiring loom - he reckoned due to the car grounding or such like. He cut out the bad section and repaired it. Cleared the codes, test drive again and all ok. I doubt I would have ever found that! But as someone said, get it checked before you start replacing parts. On the short drive back, the hybrid battery went from very run down to very well charged - green, one bar from the top. A bit early to say, but it felt like the hybrid system was charging more than needed and the consumption was lower than I'd expect in town driving. That said, it drove down our road on battery so maybe it's settling in. I wouldn't worry! This was and interesting mix of one of those things rather than a mileage related incident. If your car has good history it should be fine. What was good to hear was David said he doesn't do much work on these, which implies they don't have many issues. Happy to have the car back, driving beautifully as usual.

David Hammond of Hammond Auto Electrics in Guildford is the guy looking at it. Drove over with just the engine light on. He's had a look and found a fuse gone that (I think) is on the circuit that sends data from the MAF sensor. One of the four O2 sensors is faulty, plus some other bits I can't remember what he said! Not tragic and likely the old sensor was ok. So pleased this isn't being looked at by Lexus, they'd be fitting all sorts I expect! He's keeping the car in overnight as he needs it cold to check the rest. He also told me the AFS sensor warning light, which was on when I bought the car, is the front one not the rear, so he's done me a favour there, I was about to remove the rear one and try to fix it. He will check when it's on the ramp as it might just be a corroded wire. Good man, recommend him. Hopeful that I'll have a better car soon.

I'll keep you posted - what's your mileage? Not wishing to pre-empt anything, my problems started with the engine not cutting out, also ticking over a bit rough. It's an interesting one...