All C codes showing, but no lights or operational issues.

Has anyone run into this issue? Everything operates as it should, there are no warning lights on the dash. These codes come up, but can not be cleared.

 

Is the MIL lamp good?

 

Mil light is good.

 

I think you might have a bad ground somewhere. You could also have a bad ABS ECU.

 

Vacuum booster or no?

 

From my quick research, those codes are only stored during "test mode".

 

There's 2 other threads about those exact same circumstances posted in the last week, although I think both were posted about the same truck.

The common theme here seems to be an Autel scanner. Maybe I'll try scanning my ABS with my MD802 after work, don't remember if I've done that or not since I bought it.

 

Yes on the vacuum booster. So if I understand you, the codes are not actually present, but not actually real?

 

This may have been posted by a party that is looking to purchase my truck. this came up at a third party shop and they had no explanation for it.
thanks.

 

I've never used an Autel scanner but maybe it's setting codes because it checks them using the jumper wire method?

 

Maybe they connected the scanner but never ran the test for each sensor so they assumed it to be a problem.

Anybody can hook up a scanner. It's what you do with that info is what matters.

 

Autel makes pretty OK scanners, but unless they went legit in the last 5 years or so, their software is pirated/reverse engineered/generally a little sketchy compared to the actual manufacturer's software.

I don't recall ever seeing weird shit like that with Toyotas... only Toyota oddity I remember was it occasionally wiping out the steering angle calibration when clearing codes. But there were a few that'd pull up some oddball stuff along those lines.

 

Yeah they did not do anything beyond connecting and surmising. The potential buyer paid to get it looked over, so that is as far as we went. I don't want to put money into a truck I'm selling, but I also want to know that that I am confident with issues.

 

With the older Toyota and Lexus cars I've worked on, I had to connect the jumper wire and run each test to check that the sensor was working, the wiring was good and the computer was good, you would know this by the lights on the dash.
With the newer Techstream, you just go to the data list for what ever system your checking and see what each sensor is doing in real time. Makes it so much easier.

The only reason we would do this is if the ABS light was illuminated on the dash when it shouldn't be. If no lights were on, we wouldn't even bother running the check unless the customer was complaining of an issue (mostly ABS activating at slow speeds usually due to a bad wheel speed sensor).

 

So I took it in to a shop today. 2 separate scanners were used. Both showed no codes present.