sbenasso

So, my CEL and VSC Tac Off lights are stuck on. (They used to come on, and then go off periodically. Now they just stay on.) I bought a $27 bottle of CATClean, and ran that according to the directions. The car seems to run a bit better, (less hesitation) but the lights are all still on. I had the auto part guy hook up his computer and read the codes. This is what he told me:
C1201 - ECS Malfunction
C1223 - Malfunction Anti-lock Brake Control
C1241 - Low battery or high battery "charge"?
P0430 - Catalytic System

I'm not terribly handy, but am willing to try a few things. I know that if I take it to the Lexus dealer, they'll tell me they can fix everything for a few thousand bucks. (I don't have a few thousand bucks!)

Are any of these codes (particularly the anti-lock brake code) warning of anything that would make it dangerous to drive the car?

Thanks for any help you can offer.

Steve

mdbrown

The antilock brake control malfunction, at it's worst, would indicate you no longer have the anti lock function but your basic braking will remain unaffected so no, not unsafe. The VSC and any other such lights are on because the CEL is on. If you have not already done so, have them clear the codes and see if they come back. If all the same codes return the first one to work with is the C1241 as low voltage can cause the the 1201 and 1223 codes.

The cat code may indicate a failing cat but it can also result from one of the O2 sensors being slow to respond. You need to invest in a code reader that will give you streaming data so you can see what's going on while the engine is running.

A quick check would be to take a multimeter and check battery voltage when the engine is idling. You should get a reading somewhere between 13.1 and 13.6 volts. Much under 13.1 and you have a weak alternator or failing voltage regulator and they system may struggle when the electrical load gets higher. The digital electronics in your car become unreliable at around 11.3 volts and much under that they may become totally non-functional.

mandyfig

mdbrown, great advise. Very detailed.

sbenasso

I just had the alternator replaced a few hundred miles ago. I don't remember the mechanic even mentioning the voltage regulator. I guess I assumed they would have checked that when they replaced the alternator, but that might not be true. Is it possible that the battery never got back up to fully charged? I can go have that checked easily enough.

As far as the scan tool goes, there appears to be a wide range of price and functionality. Again, I'm pretty unsophisticated when it comes to this stuff. Would you recommend any of these?
The auto parts guy said it's most likely that the catalytic converter is dead, given that the car has 195,000 mile on it. Seemed like a pretty broad statement to me, but I guess he could be right.

I'll take of making sure the battery is back up to fully charged, have the codes reset and go from there.

Thanks again!

mdbrown

I would likely go with this one:
As far as the cat, it may be failing but it won't cause the 1201, 1223, and 1241 codes. Those need to be dealt with first. The voltage regulator is internal to the alternator. First things first, measure voltage at the battery with the engine at idle - 13.1 - 13.6 is a typical range. Anything under 13 volts or over 14.8 volts and you either have a bad alternator or possibly a shorted battery (unlikely as the vehicle starts and runs but a bad battrey can develop a surface charge and start a vehicle under optimal conditions.)

If the electrical system is below proper voltage it can create all kinds of anomalous codes. That needs to be where you start your troubleshooting. Strategy based diagnostics can save you a great deal of time, money, and frustration.

sbenasso

So...I went to the Interstate Battery store. (It's an Interstate battery, which I know shouldn't make a difference, but that's where I bought it, and it was convenient.)

With the car turned off, it measured 12.93 volts. I asked him to check the battery when the car was idling, and he looked at me like I didn't know what I was saying, but he did it anyway. He predicted that if the alternator was in good shape, it would read somewhere right around 14. It read 14.2. Battery rated at 800 CCA's, measured at 817 CCA's.

Went to a mechanic who said they would not reset the codes. They wanted to do a full diagnostic and said if the car has "codes", there's a reason, and that resetting them could cause them not to come on when they should. I guess I'll have to order the OBD2 and wait, unless I can find a friend who has one.

Just curious, was the $27 for the CatClean just money wasted?

Thanks!

mdbrown

Don't know but you are getting some odd codes. Looks like the battery and charging system are in good working order. You need to erase the codes and drive it. If the CEL comes back on go from there, if they don't then it may have resulted from the alternator change. In any case, I'd find a different mechanic.

RedGemini

Your mechanic doesn't know what he's talking about. A reset will have zero effect on how reliably the light comes on. If anything, it will help tell you the severity of the issue(s) you're dealing with. If it pops back on pretty quick (next or even same drive cycle), then there is a problem. If it takes a while, it means a problem is in the works. If it never comes back on, then it was a fluke.

As for CataClean, I used a bottle when mine threw a P0430 over 2000 miles ago, and it hasn't popped back up. I did, however, get a light a few days ago for P0037 - Bank 1 Sensor 2 - downstream O2 sensor heater circuit. I cleared it, and it came back on the next drive cycle, meaning it's bad. I found a Denso on eBay yesterday for $71.95 shipped, and it'll be here Friday.

So, did I get the P0430 because the O2 sensor was starting to flake out? Who knows? I'd guess maybe not, as the O2 sensor has a heater circuit issue, but anything's possible.

sbenasso

Thanks MDBrown and RedGemini for your help. I really appreciate this. I'm sure I'll end up having to pay for some parts and repairs, but feel that research will help me focus on the real problem(s), and not pay for things that aren't broken.

Another forum said that starting with the air filter and working backward through the system, is a good idea. After the filter is checked or replaced, check and clean the mass air flow sensor, then the PCV valve (replace probably) and then replace the spark plugs and perhaps wires. (I need to check my files to see the last time this was done.) It was also suggested that cleaning the O2 sensors might help, prior to merely replacing them, although that sounded a bit more complicated. (Rock Auto lists a bunch of O2 sensors with a wide range of prices.) http://www.rockauto.com/en/catalog/lexus,2004,rx330,3.3l+v6,1421312,exhaust+&+emission,oxygen+(o2)+sensor,5132

In case it's the catalytic converter, I had these questions. Are there 2 or three catalytic converters on this car? Are they welded on or bolted on? I have a muffler shop that probably won't charge me too much to put them on. This page from Autozone has some. Would the one for $103 work on my car? http://www.autozone.com/emission-con...er/lexus/rx330

Trying to educate myself a bit, and sure appreciate you guys.

mdbrown

You don't clean an O2 sensor, you replace it if it's failing. Second, don't throw part/service at the car as those things you are listing won't cause the codes you are getting anyway. Strategy based diagnostics... can't recommend it highly enough.


Without seeing streaming data there really isn't a reliable way to know whether the cat is weak or an O2 sensor is slow to respond. If you live in an area with smog checks you can get them to sniff the exhaust - if your hydrocarbons or carbon monoxides levels are too high it's possible the cat is on it's way out. Again, clear the codes and drive. If those same codes come back then deal with the PCM codes before you do anything else.

sbenasso

Thanks again for all the advice.

So, I borrowed my auto parts store's OBD2 reader and reset the codes on my own. Is it my imagination, or could the car actually be running better just as a result of having done that? All the lights are off, and the car does seem to be running smoother. I haven't driven the car all that much (maybe 30 miles) since I reset the codes. None of the warning lights, including the CEL, have come back on. Is there a general rule of thumb here on how quickly the lights would come back on, if they are going to? Thanks.

05RX330AWD

<br /><br />From personal experience when I first purchased my RX330 the codes P0420 &amp; P0430 were present since most likely the previous owner was refueling with the cheapest fuel available.Since then I was refueling with 91 Octane Fuel, after some time erasing codes, they would not reappear. Fast forward a couple of months later, only the P0430 would come up, erase the code, it didn't reappear since. There is no set pattern although the 91 Octane fuel helped, now I downgraded tho 89 Octane fuel due to costs, no codes as yet. <img src="https://www.clublexus.com/forums/images/icons/icon14.gif"/> Hopefully this helps some.