Jeff92se

Just got a call from the mechanic. Non-Lexus btw. But everyone should have an obd-II code reader. Anyhoo. Said the CEL was for a random misfire on the injectors. He claims the injectors need to be cleaned. Recommended the Motovac (sp) system service. $260! Decent price?

Also said the waterpump was leaking because the coolant level was low. Seems sorta suspicous. Do waterpumps go out frequently on this motor?

How do you clear the cel anyway?

mikey00

I have owned 2 RX's and have been on this and other Lexus forums for a few years now and this is the first I have heard of injectors needing cleaning. I know some do clean them as prevenative maintenance but the need is questionable. My first thought would be the code is due to your gas cap not being on tight but a mechanic can't charge much for tightening the cap so he goes for a $260 injector cleaning. This guy may be completely honest and I may be way off base here but thats my thoughts. Also I have never heard of a RX water pump leaking but anything is possible. If you want to clear the code yourself, simply disconnect the battery for a few minutes or pull the EFI fuse (#13) for about 10 seconds.
Mike

Jeff92se

Thanks. The thing is the water pump is under an extendend warranty. I can't see them doing that on purpose. I find it odd also that they conclude the WP needed changing based on a slightly lower coolant level. I guess I'll have to make sure to request the old parts and to have them specify the specific error code.

HarrierAWD

Is the extended warranty with Lexus or AAA? The shop can get the money from the warranty underwriter, so they make money. Coolant level fluctuates. On my RX300, it's at half point when cold, at F when hot. Even if there is indeed coolant loss, it could be a number of things (leaky radiator, leaky hose, loose cap, etc.) Water pump seems very unlikely.

Also not to accuse this shop of anything, but fuel injection cleaning is a very common auto shop scam. They charge you hundreds for pouring in a bottle of STP ($1 at Walmart.) Unless you have reasons to trust this shop, I suggest you take your business elsewhere. If money is an issue, you can always go to a Toyota dealer for service. The RX300 is mechanically identical to the Toyota Highlander.

Jeff92se

The Warr is from a non Lexus dealer. I'm just worried they might screw it up more than before.

They also want to use Dexetron coolant. Do the RXs required Toyota red coolant or is there an Dexetron I or II etc.. equivalent?

rxdriver

RX300 and 330 use Toyota ATF Type T-IV. It's not Dexron III.

I've heard that several carmakers each have their own name for the current flavor of ATF, like Toyota T-IV. There's a Ford version, a GM version, etc. Despite the name difference, they're all the same fluid. There should be a generic equivalent, but maybe right now someone has the patent tied up?

HarrierAWD

Jeff92se: I highly recommend that you bring your RX elsewhere. Dexcool is formulated for some GM cars, not for Toyota. Don't let them pour it in.

Rxdriver: Each manufacturer has its own tranny fluid for a good reason. They have different viscosity requirement for their trannies. Tranny will shift funny if a wrong fluid is used, and will result in damage overtime.

Jeff92se

Odd situation

They couldn't figure out how to hook up the machine for the motovac so they didn't do it. They recommeneded I put a couple of cans of Techron and see what happens.

Looks like they did the water pump. They said they were going to use Dexcool (which is green?). I took a look inside the overflow reseviour and the radiator. All red. So they either topped it off with water or actually used some Toyota red coolant. Nice!

Question. They reset the code but it came back. I assume it's the P0171 System Too Lean (Fuel Trim)

. What is the recommended fix for this? The dealer said it didn't specify anything.

HarrierAWD

Dexcool is orange.

Good luck.

Jeff92se

Thanks. Does anyone know the accepted diagnostics procedure for a P0171 error code?? Does it point to any specific part?

Traturn

Have to make sure the A/F sensors are working properly, thats the first step. If they are, the code is likely set by the MAF sensor near the air cleaner. MAF sensors are more common failures.

The MAF comes off with a couple screws. Shine a flashlight at the pintle inside and look to see if its 'gunked up' or clean. If it looks clean, more likely to be one or both of the A/F ratio sensors.

mass airflow sensor & air fuel ratio sensor btw.

Jeff92se

Thanks. I ran a search on google for P0171 DTC codes. It seems these obdII codes are fairly common across brands/makes. What I came up with was the same conclusions as yourself. So thanks for the reply. It's nice to have a confirming remark to back up some simple research.

I plan on buying a OBDII code scanner that also does simple monitoring of sensors. Nothing too complicated or expensive. Maybe a tool that uses a Palm of some sort. I've seen a few on maxima.org where I'm a moderator.

Our RX300 is due for it's 60 tune up. So in addition to your suggestions, a new fuel filter/air filter/plugs/etc. will go in. I'm also going to try a few cans of Techron.

mikey00

Remember, the RX is not due for a tune up at 60K. Of all the items you listed the only one requiring replacement at 60K is the air filter. I bet after changing all these items you will still have your code to deal with. My suggestion is that rather than randomly changing good parts is to have someone diagnose the problem. It is most likely the MAF sensor or the Oxygen sensor as someone mentioned above.
Mike

wantalexus

I had this happen and went thru many of the steps you are describing. What it ended up being was a vacuum hose on the air filter case. It is very easy for this to come off when you change or remove the air filter. I got my oil changed at a quick stop oil change place and this came off when they looked at my air filter. 15 min after leaving I notice the check engine light. The code indicated that it was an oxygen sensor or something and I had that changed at the Lexus dealership. Light comes on a day or so later. Went back and they found the problem. No charge for the second visit but very aggravating even though they gave me a loaner to use and treated me like a king...just a headache putting a car in the shop.

This has happened a couple of times since then, but I just put the hose back on and have the light reset at a local auto parts store.

Jeff92se

Update. I just put some techron in the tank and inspected the MAF. It's very easy to undo two screws and lift it out. There was indeed an oily film on the side of the hot wire that points toward the filter. So I sprayed some electronics cleaner on a Q tip and carefully cleaned the hot wire and the blob of resin at the tip. Installed the maf and started the car. Starts fine. Now to reset the CEL and see if it stays off.