minorkeyle

Hello All. I've searched, read and have generally been losing my mind. My 2000 RX300 FWD has turned into a money pit. I'm trying to determine if the vacuum switching valve on the air box, below the MAF could be part of the problem. It took me a while to identify the part, but it is definitely 90910-12227. I looks like the hose fitting from the back of this part has been broken, and obviously no longer connects to the line running down, and into a metal line. Someone has tried JB welding it (including my mechanic) but all attempts have failed. My mechanic maintains that it is not part of the problem, but I'm pretty sure it is.

Backstory: Leave on a family weekend vacation. It 100 deg.F, and we're running up the hill towards Santa Fe, NM at about 80 mph. I start hearing what I believe is valve noise when I really get on the throttle. Engine temp is fine. We reach our exit to start heading to southern Colorado and all of a sudden, I have no overdrive. I've since learned that its OD lockout caused by CEL. Of course the first place I take it, a transmission place, says my tranny is shot. I don't believe them, and keep investigating. Mostly on this forum. Meanwhile, I take it to my mechanic. While this is happening, he says we should really do the timing belt and water pump (we've been talking about this for a while). So I say, go ahead. Another thing we have been meaning to do is fix an existing vacuum leak causing a CEL that he identified as the brake booster. So, we do that too. Obviously, we're hoping that the vacuum leak is the culprit. After he does the booster and timing belt, we get codes for both knock sensors and both upstream O2 sensors. AHHHH. And still no overdrive. So again, I'm looking at this vacuum switching valve and wondering if i really should have spent the money on knock sensors, harnesses and O2 sensors. Mechanic has not installed them yet, and I'm wondering if I should hold off and get the switching valve first.

Codes he has pulled. Sorry but I don't know which ones were before, and which ones were after timing belt and brake booster: he wrote them in groups (1346, 1150, 1130)and (171, 325,330)

Sorry for the novel... I would greatly appreciate some advice.

minorkeyle

Should have mentioned mileage. 145,000. Really hoping someone will chime in.

salimshah

Welcome to Club Lexus.

Have the CEL cleared and then read the codes on the first onset of the CEL.

Get the broken pipe from a salvage yard.

Salim

minorkeyle

I/we have. Hence the two sets of codes. The set with '171 I' now know is a code after timing belt, booster replace. 171 is pending.

salimshah

For my feeble mind can you please list the current codes

Alpha #### [where the Alpha is typically P and each # stands for an integer.

Salim

Lexmus

minorkele,

If you don't already have one, you should buy a code reader. I have the Autel MS300, which is only $15 from Amazon, as well as several bluetooth ones (Veepeak mini bluetooth works well) that I read with Torque app on android. Veepeak also sell a wifi version that works with the iphone. That way you aren't having to run to the mechanic or AutoZone to read your codes. Plus you can reset the codes and see if they return.

maxSteel

Assuming this is a P0171, the diagnostic says these are the trouble areas:

• 
  Gas leakage on exhaust system
• 
  Air intake (hose loose)
• 
  Fuel line pressure
• 
  Injector blockage
• 
  Mass air flow meter
• 
  Engine coolant temp. sensor
• 
  A/F sensors (bank 1, 2 sensor 1)

Given some of your other description about broken hoses and such might be the second item.
First check that air intake hose people forget to reconnect.
After that try spraying carburetor cleaner in the area where you suspect a vacuum leak. Engine rpm will change when it gets sucked in.

Pzindy

I know the P0330 is a knock sensor code (and I think the P0325 is also). I know that code will eventually lock out overdrive. There is a thread here about DIY replacement of these. It is not difficult, but does take a lot of time. Expect to pay for at least 5-8 hours of labor to have a shop do it.