Yellow light on dash ?

[scott degroot]

l1tech,

I grant you that the error codes do not always pinpoint the exact failing part (as your BMW customer found out) but it does point you in the right direction.



Had he not already replaced the O2-Sensors, you probably would have first thought they were bad and had to run diagnostics on them as well and charged him more. Since he already replaced the O2-Sensors, that's the most obvious solution, and so you were able to look at something less obvious. That should have saved him some money in diagnostic services?? And he does have two new O2-Sensors and peace of mind that they should last for a little while

Never have I ever pulled a lean code for both bank 1 and bank 2 and thought to myself...hmmm I bet the O2 sensors are bad...that dog don't hunt and any person who thinks they know anything about diagnostics adn comes to that assumption should never be allowed to hold a wrench. 99.9% of the time you get a lean code on both banks of a maf equipped engine you have false air entering somewhere behind the maf sensor. O2 sensors...ha...when is the last time you saw 2 oxygen sensors fail at exactly the same time?? So no my first thought in the BMW situation was a vacuum leak which was verified with propane...it actually took longer for the scanner to boot up and retreive the code than it did for me to locate the issue.



In regards to your Toyota. I wouldn't have looked at the so called "diagnostic printout" form the parts store either as it had nothing on it other than a code, which I am sure was some sort of evap leak code and being that there is no code for Toyota vehicles that states the evap canistor is faulty the system would have to be tested and being that Toyota evap systems are overly complex the charge would have been appropriate.

 

[Wayne Partridge]

Well ford replaced the front crash sensor infront of rad. took off half hour labour.

part cost aprox 75.00 dollers cdn 90 bucks to check it half hour to install a screw and put back a couple covers.

Thanks till the next issue.:cry:

 

[Richard L]

i1tech,

I agree that it would be highly unlikely that both O2 sensore would fail at the same time. My point was that a lot of unscrupulous shops who are only looking to make a quick buck will replace the 02 sensors and charge the guy even when that was not the cause of the CEL. As well as I think there are a lot of so-called techs who do not know how to diagnose problems....If the code says the 02 sensor is reading a lean condition, they assume the 02 sensor is at fault.



As for my Toyota, the diagnostics I got from AutoZone had two codes and two separate lists of possible causes for the codes (each list was about 15-18 inches long on cashregister tape). Basicly they said that it was the evap canister, bad or loose vaccum hose, or bad gas cap. I bought a new gas cap since that was a simple $10.00 fix. I also got under the vehicle checked for any loose or broken hoses going to and from the evap canister. I also looked under the hood for any cracked or loose hoses and found nothing.



The Toyota canister comes with a control mechanism attached to it. The service manual I have indicates that they are two separate parts, but recommended replacing the control module with the canister....That must be standard practice because I could not locate anyone selling the canister separate from the control module and everybody wanted about $600 for the parts



...Rich

 

[scott degroot]

RIchard L



What are the codes?



The BIGGEST problem that arises with the evap system is the canistor closed solenoid located on the backside of the air cleaner housing. Alot of times when servicing the air filter the vacuum line will become detached. I have also seen the wires to the solenoid get messed up becasue of the same thing. If the vacuum hose at the solenoid itself is connected look a littel further down adn you can see where it connects to the metal pipe...it will come disconnected there as well.



Evap systems are a pain in the but and alot of people will drive around with them illuminating the check engine light becasue "it drives fine" and what you do with your vehicle is your own choice..I don't have a problem with that. My only thought is that if your check engine light is already on how do you know if another problem develops that could potentially cost you alot of money if not caught quickly but you have no clue becasue the check engine light is already on???

 

[Richard L]

l1tech,

It sounds like you are absolutely correct. The codes are P0446 & P0440...but I misread the causes. The list contained other codes for other brands of foreign and domestic vehicles.



For the domestic (US cars) it could be the evap canister, fuel cap, or vacuum leak, etc. For my Toyota, all the causes are related to a faulty purge solenoid, open/short elec circuit, or bad electrical connection related to the purge solenoid.



Also, when you mentioned messing with the air cleaner could detach a vacuum hose, I recall that sometime before I got the CEL, I had replaced the old air filter and had difficulty getting to one of the cover latches and ended up lossening some other parts to get at the latch. I may have knocked a hose or electrical connector loose. I just think that it was several months before I got the CEL, but it may have taken that time to vibrate loose, and I don't drive the Toyota that much anyway.



I will try to check it out later this weekend or early next week and will let you know what I find....but I am thinking that you may have hit my Toyota's problem right on the head...from long distance..:grin: Had you not asked for the codes, I would not have reread the printouts and realized I was reading the P0446 and P0440 causes for domestic vehicles and not for my Toyota...then everything started to fall into place. Thanks.



...Rich