CEL and VSC lights on

[LIRunner03]

So driving home the other day the CEL and VSC lights went on.

Changed gas cap since truck has 163K miles and reset codes. Lights came back on about 15 mins later.

Every time I start truck the vsc light goes off for about 5-7 sec and then goes back on. CEL is always lit.

Truck drives fine, idles fine, still getting over 17-mpg and no weird smells. I ordered the brake light switch so will see if that's it otherwise I will perform the ZPC although my truck has not been hooked up to anything so not sure that would do anything.

I do have the exhaust manifold tick (leak) like most of the V8's, but have had that for the last 100K miles.

 

[paperchasin]

Can you pull the codes and post them here?

 

[LIRunner03]

Yes, although I wont have time until the weekend.

 

[LIRunner03]

Finally got around to pulling the codes and it turns out the Bank 1, Sensor 1 O2 sensor is showing inefficient. I ordered a Denso O2 sensor and already had the BLOX O2 sensor extension on order.

I had a feeling it wasn't the CATs, due to the truck running Great, smooth idle and getting 17+ MPG.

I did in the meantime, put on a new OEM gas cap and brake light sensor prior to pulling the codes.

Should hopefully have this taken care of by the weekend.

 

[blackoutt]

Just a pointer since it's not 100% clear in your fault code descriptions, DO NOT space out either of the upstream O2 sensors (air/fuel ratio sensors) it will not run properly. People only space the downstream O2 sensors (catalyst efficiency sensors) to trick them for emissions fault codes reasons, or if primary catalysts are removed.

 

[LIRunner03]

Correct, its the bank 1 sensor 1 so no need for the BLOX O2.

I bought them as a safety prior to getting the truck checked in case it was the downstream's.

 

[LIRunner03]

Had a few minutes today and changed the O2 sensor. No more lights!

 

[NfmsKW]

So, I have had a similar issue recently. CEL and VSC TRAC lights on. Had been running rough intermittently. Took it to local mechanic 3 days ago and was told to replace ignition coils, spark plugs and also serviced fuel system. They said that I had been having countless misfires, etc. 4runner is driving fine, but lights came back on 2 days ago.

Went by autozone and had codes pulled. They found a C1201, C1223 and PO430 codes. After some reading and searching here and online, seems this could be O2 sensor. Does this sound right to y'all or could it be something else?

Wanting to try fix myself if possible (especially after what I just paid the shop) but don't want to just throw parts at it without understanding what is wrong.

I have 238,500ish miles on my 2004 sr5 if that helps any.

Any help would be apprciated

 

[lightfreak]

So, I have had a similar issue recently. CEL and VSC TRAC lights on. Had been running rough intermittently. Took it to local mechanic 3 days ago and was told to replace ignition coils, spark plugs and also serviced fuel system. They said that I had been having countless misfires, etc. 4runner is driving fine, but lights came back on 2 days ago.

Went by autozone and had codes pulled. They found a C1201, C1223 and PO430 codes. After some reading and searching here and online, seems this could be O2 sensor. Does this sound right to y'all or could it be something else?

Wanting to try fix myself if possible (especially after what I just paid the shop) but don't want to just throw parts at it without understanding what is wrong.

I have 238,500ish miles on my 2004 sr5 if that helps any.

Any help would be apprciated

Do you have the ABS light on as well?
You may have couple unrelated issues going on here.

The C codes are generic ABS brake system fault codes. Common problems on our 4runners is the brake light switch failure and abs sensor wires going to the hubs being damaged. Both are easy DIY fixes.

The P0430 code is discussed on in detail on a few threads, it's likely a downstream O2 sensor although exhaust leaks can cause it so might want to check that first.

 

[LIRunner03]

NfmsKW May want to replace your gas cap if its the original as well as the brake light switch. Both are very inexpensive and can trigger the VSC lights and C codes.

 

[NfmsKW]

ABS light is not on...but I have noticed yesterday while driving that the tire pressure light is blinking. don't know if that makes a difference.

thanks for the suggestions. Maybe I will start with the brake light switch and cap this weekend and see what happens.

 

[LIRunner03]

make sure you pull the positive battery cable afterward to reset for a minute.