Test and repair here. We test and fail them unless the customer specifically asks about the light. Even then, as quick as it is to run an OIS test, we usually test 2000 and newer vehicles and fail them before starting the diagnosis of the CEL. The reasoning is: What if you finish fixing the CEL and then go to smog it only to find a broken pcv hose or something else that will cause it to fail? It's better for the customer to know everything they need to fix at once.
I let them know before the test.
I learned early on that some things are not worth getting shot or get in to a heated argument,plus %99 of the customers return after repair and they trust you more,this has been my experience so mileage may vary.
I test them with the MIL on unless the customer asks about it before I begin the work order. Or sometimes I reject them if I sense the customer is going to be a headache. In my experience, when I tell people about their MIL before the test, they never come back. I'm assuming they just take them to a clean-plug shop and get them passed there.
Also, I've come to realize that if you fail a vehicle with the MIL on, DON'T mention the actual light. Instead, say that it failed because the smog machine picked up on trouble codes that are stored in the computer. Once I learned that I should explain it that way, most of the complaining stopped.
I don't test them. I tell the customer it will fail. I bet about 50% come back but I have a very good reputation and a lot of referrals so I think it has paid off. There are times that it is quiet and I would like to just test it but generally when I send one away there is another car waiting to come in.
I used to test them and tell them it failed because the code is an emissions related fault. I would then retest no charge but after two times of someone telling them that it was a guaranteed fail and I knew it (the truth) I decided to quit doing that. It works for me and my fail rate is still where it should be.
People are usually shocked when they find out I'm not a very good electrician.
I don't. I tell the customer that if the light is on the car will automatically fail.
I tried doing that with one guy, and he told me that I was wrong, and to just test it. I did. I wasn't wrong.
I have been interrupted a few times (while getting ready to pull a car in to test) by owners who stopped me so they could disconnect and reconnect the battery, or disconnect an EGR or air injection vacuum line. Amazingly, their efforts went unrewarded. I shit you not ...
“Never attribute to malice that which can be adequately explained by stupidity.”
I test the vehicle as it comes in.
This way they get to know what set off the light, and they get a free retest anyway. Whether we fix the problem or they go their own mechanic, I get a fail and they get their smog.
Occasionally I will get a customer who gets mean and rude, but that type of thing comes with the job.
If you're not testing them you're hurting your SVFR and FPR, if you don't test them you will have close to 0 failures, that is hurting you.
Cars don't fail for MIL light, this is a symptom, the reason the light came on is the reason it failed, don't discuss the MIL with customers, talk about the code printed on the VIR, that is why it failed, no good reason to reject these cars.
Customers getting upset at you because their car failed? If you're afraid to fail a car do something else.
Since we're on the subject of check engine lights, anybody think renaming the light/icon/symbol would finally get people to realize something is wrong with their car? I get customers all the time who say "oh my check engine light/service engine soon light is on but that's just because I need an oil change" etc.
So I think if the vehicle manufacturers were to change it to a "Emissions Malfunction/Engine Malfunction" icon, people would actually believe it and thus take their cars into a shop for service. Thoughts?