72rsmike

Hello All. I have been lurking here for a while and I just bought a 2007 Lexus IS350 about 1 week ago (96k miles). I had the car inspected at Lexus of Naperville (I live in Wheaton, IL). The car drives very well, no weird noises and it has had all the recalls done. The previous owner was meticulous about oil changes and everything was done at a Lexus dealer. The pre-inspection at Lexus told me a few things that need to be fixed:
1. They said exhaust has a small hole in the y-pipe. In negotiations for the car, the seller (used car lot) has agreed to repair the hole in the exhaust.
2. They said that the front brakes need to be replaced soon (pads and rotors only). They also agreed to replace these, but they do currently work fine.
3. They said that the rear caliper slides are getting stuck and need to be lubricated.

I drove the car for about 160 miles and the lights started turning out....not happy. The car still appears to run well though.
It says Check VSC, the check engine light is on, the traction control light is on and the exclamation point in a triangle is on too.
The codes that came up from O'Reilly's:
C1201
C1241
P0430

Which mean:
C1201=Engine Control System Malfunction
C1241=Low Battery Positive Voltage
P0430=Catalyst System Efficiency Below Threshold Bank 2

I have read a lot of differing issues people have, but I was hoping someone might have input. Do you think these all could be caused by the exhaust leak? Is there something else common I am missing?

Thanks in advance!

Bichon

P0430 is definitely the exhaust leak in the Y-pipe. It's possible the C1201 and C1241 may have been triggered inadvertently during the inspection, or if the battery was recently replaced. After fixing the Y-pipe, clear the codes and see if they come back.

72rsmike

I will have to check the date on the battery, no idea how old it is. Any idea what would cause the C1201? How would that happen during the inspection?

My theory is that the place I bought it from cleared the codes and it now has enough miles for them to come back. If the Lexus dealership had plugged in, would it tell them that the codes were cleared? Or is there any red flags that should have come up from them?

Bichon

Yes, the dealer should have been able to tell that emissions-related codes were cleared if brought to them before enough drive cycles have been completed for the diagnostic trouble code to come back. There are "readiness" flags that show whether the diagnostic self-tests have been completed since the last erase operation. The Ohio EPA has a pretty comprehensive description of how this works: http://epa.ohio.gov/Portals/27/echec...riveCycles.pdf

Gville350

iTrader: (10)

i can tell you this, if your battery or alternator are not running at 100%, that the car will trigger various odd codes to sensors not getting their needed voltages. Definitely look at both the battery AND alternator.

72rsmike

I will have to take a look at both - I am sure there is somewhere on this forum that says what output to expect from the alternator..

72rsmike

Another weird thing about the lights is that they have turned on and off again.
~156 miles: lights on while driving (VSC, check engine and no traction control)
~200 miles: light are off after starting the car. when I parked it they were still on..
~280 miles: refuel and lights are still offf
~6 miles on new gas: all the same lights are back on

Any idea why they would turn on and off? Is something intermittently failing? Hoping to get the exhaust patched this weekend to rule that out first. Then I will look to replace O2 sensors if needed.

Bichon

The exhaust leak causes intermittent P0430 (or P0420 if the leak is on the other side) codes. Basically what is happening is that the leak is venting some of the hot exhaust gasses, causing the catalytic converters to take longer than normal to light off after a cold start. The OBD2 catalyst efficiency diagnostic runs at the point in the warm-up cycle when the cats should have lit off. If they have, the CEL turns off (or stays off). If they haven't, the CEL turns on (or stays on). If you were to wait a bit longer and your exhaust leak becomes larger, the CEL will stay on permanently.

ianbis

It appears, these vehicles (Toyota/Lexus) were designed to illuminate the VCS and Traction Control warning/ lamps/ message whenever the CEL comes on. I have had to clean my MAF twice now in 55k miles and both times the CEL illuminated the Traction Control/VSC warnings/messages/lights also illuminated on the instrument cluster.

Bichon

That's because the ECU disables traction control whenever the CEL is on.

ianbis

Thanks for confirming

72rsmike

Thanks Bichon and ianbis for the input. I hope to get the exhaust repaired next week and I will clean the MAF this weekend. It would be great if it was as easy as that to fix.

ianbis

You’re welcome 72, just wanted to clear up that the VSC & No Traction will illuminate whenever the CEL illuminates for whatever reason. I did not mean to suggest that your MAF needed cleaning.

72rsmike

Little update:
I had the shop repair the hole in the Y-pipe and got new disks and pads on all 4 corners. They reset the CEL (I assume, since it was off when I got it back). I have put about 70 miles on the car since I got it back and the CEL has not turned back on. I will check back in around 150 miles since that is when it first turned on, but I am hoping that the exhaust was the issue.

I also purchased new spark plugs since I have no idea when they were last changed and figure it can't hurt. Now I need to do some more research on other maintenance to do before I start modifying anything.

72rsmike

Update #2: It has been close to 300 miles now and still no CEL!! I think that the exhaust leak was the issue. Strange that it threw so many codes, but I am glad it is fixed.

And as a Christmas present for my IS, I bought a set of Blizzaks on 225 45R17's from an IS250. I am certainly a believer in the winter tire now...it handles like a champ on slippery roads.