Why diagnosis is important.

[dan]

Engine light comes on on my grandpas 2010 Buick Lucerne, he finds a code for Evaporative Emissions system gross leak, the guy who scanned the car for him tells him its the gas cap without even looking at the car, he erases the code, and my grandpa drives the car the engine light comes back on after re tightning the gas cap, well he goes back again, he is again told its the gas cap and to replace it!

Now… he was even skeptical and he asked me to look at the car, first thing i did was checked all the lines under the hood for the Evaporative emissions system… all good no cracks, or leaks, all the lines running under the car good, all the lines going to the gas tank good, charcoal canaster good, so after inspecting everything for damage that would cause a gross leak, also the gas cap was in perfect condition! i then went to the purge valve! this is a common issue with GM cars, it goes out, trips a engine light for a gross leak… so its a pattern failure, its the only thing really left that could be causing the issue, i replaced it, take it for a test drive… fixed!

So lesson learned here, don’t make assumptions! Diagnose!

Topic

[none]

There’s a touch of irony in what some people will do to avoid a labor charge to diagnose it though. They make that effort to avoid the charge by throwing parts at their car based on hearsay or something they read on the internet and then they burn up the value of the diag charge and then some guessing the wrong parts at it. If it wasn’t for you being able to diagnose that car the right way, he might have got himself suckered into a vent solenoid and then a canister before finally getting sold that purge solenoid.

[wafrederick]

I seen it a lot with lots of car problems misdiagnosed.One was a Jeep in that AutoZone misdiagnosed as a bad alternator and it was the battery that was bad.There was nothing wrong with the alternator doing the testing right.Another one was a grinding noise in the rear.Customer had a cousin of his install rear brake pads and said it was a bad wheelbearing making the noise.Pulled the rear wheels and it was a simple diagnosis called rear brake pads installed incorrectly.They were installed backwards metal to metal.It is the same with car auctions too.Dad bought a Chevy Cobalt and they said the transmission was bad.Transmission was not bad,the previous owner ran into something on the right side bending the lower A frame also ruining the axle.I replaced the lower A frame and axle and the transmission worked fine.Another one was an Oldsmobile Cutlass Supreme,auction said the engine was bad,would not start and was not bad.Looked at the gas gauge,on empty and was out of gas.Put some gas in it and ran.

[dan]

its like the girl i changed a camshaft position sensor for on her Chrysler seabring Touring got advice from the Jiffy Lube boys… i shook my head… “They told me my tires are too big!” she says as i tell her her front end sags down too low, no your ride height is down too low probably from warn out springs!

still no listen.

[dan]

[quote=”no_common_sense” post=147053]There’s a touch of irony in what some people will do to avoid a labor charge to diagnose it though. They make that effort to avoid the charge by throwing parts at their car based on hearsay or something they read on the internet and then they burn up the value of the diag charge and then some guessing the wrong parts at it. If it wasn’t for you being able to diagnose that car the right way, he might have got himself suckered into a vent solenoid and then a canister before finally getting sold that purge solenoid.[/quote]

Some truth here i guess, when your grandson is a certified mechanic i guess it has its advantages, i think my grandfather knew better, its things i do for him because he lets me use his garage, and simply and plainly because i have a lot of respect for him and to say no i think as his grandson would be disrespectful! so taking 15-30 minutes to look at his car check things over, plug a scan tool in and fix it… no problem.

[Jason White]

It seems that being a mechanic is kind of apart of the man-code, so everyone, their dad, and brother is a mechanic. Of them, there are three, two in particular that really eark me. Emmissions inspectors and tow truck drivers are the two worse. Two jobs in our field where you do not need to know ANYTHING about the systems to do the job, but it doesn’t stop them from trying to be “knowlegable” They put it in the customer’s head and then you have to talk them out of it. Last but still annoying is parts store guys. They usually know a good bit but usually aren’t qualified to do diagnostic work. Jiffy lube types are within the radar of those.

What amazes me is how on other forums I go on when people ask questions on thier car when they are not running right or broken down, everyone has an answer but me, and I’m the most qualified of any of them most of the time.

[quote=”no_common_sense” post=147053]There’s a touch of irony in what some people will do to avoid a labor charge to diagnose it though. They make that effort to avoid the charge by throwing parts at their car based on hearsay or something they read on the internet and then they burn up the value of the diag charge and then some guessing the wrong parts at it. If it wasn’t for you being able to diagnose that car the right way, he might have got himself suckered into a vent solenoid and then a canister before finally getting sold that purge solenoid.[/quote]

I have seen all too many times people throwing parts at a car, spending hundreds of dollars and not to mention the cost of time and goody’s headache powder trying to fix a car and sometimes cause more problems in the first place. However, the problem is that so many shops do the same exact thing!

[Author]

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