New Cougar Forum banner

Status
Not open for further replies.
1 - 10 of 10 Posts

·
Registered
Joined
·
5,817 Posts
Discussion Starter #1 (Edited)
A lot of people go to Autozone, Pep Boys, or own their own handheld PCM scanner to read error codes when the CEL comes on. This is a good way to get a headstart, but those codes do NOT tell the whole story.

Facts: A CEL can come on for many reasons. People tend to think the CEL is only related to the emissions, which is not true. A bad cam or crank sensor can trigger a CEL, so can an ignition problem such as coil, all though a miss will trigger a flashing CEL. A vac leak, vapor leak, fuel sensors, and other emissions issues can obviously trigger a CEL as well. But don't assume a CEL is only related to the exhaust.

The reason for the PCM to read and store DTCs is a way of pointing you in the right direction. A code will basically tell you what area of the car you need to be looking at. In other words, a CEL is a the cars way of telling you that it has a problem. Now if you have no idea why you have a CEL, you might start looking at the o2 sensors when in fact you have a faulty cam sensor. So you pull the code and it tells you that you have a strange reading from the cam sensor. The code points you in the right direction.

The code does NOT tell you what to replace. I know that a lot of people want to read their code, find out it is a code for "bank 1 indicates lean", and replace an o2 sensor. However that is not always the reason you get that code. Assuming that is what it means might work for you, but more likely than not, you will be wasting your money.

A lot of people dismiss the dealerships because they don't want to pay the $80 or so for a diagnosis. But many of those same people have no problem letting Pep Boys scan their code, then they start throwing parts at their car. Look at the threads in this forum, there are plenty of "My car had code pXXXX so I replaced the _____ sensor, but the code came back....so I replaced the ______, and it came back again." Basically that person refused to pay the diag fee because they felt that it was a rip off, but they flushed $150 down the toilet trying to guess what the problem was because they read an error code. It happens all the time.

Granted many times people get it right, and there are some codes that are pretty cut and dry. But more often than not, throwing a part at a car because of an error code is simply a waste of money.

After reading an error code, there are more steps to take. Pin-point tests, monitoring sensor readings under variable engine conditions, testing specific sensors. There is a lot more to it than just reading the code.

Having your PCM scanned for free at Pep Boys, or by yourself with a hand held is not a bad thing. It is a great way to get an idea of what could be wrong. But before you start buying and replacing parts at random because you THINK the code was telling you to, that is where you need to stop. Before you waste your money on parts you might not need in the first place, consider paying the diag fee and finding out EXACTLY what the problem is. Also letting people tell you their personal history with an error code or a symptom isn't always the same resolution for you, even if you display the same symptoms. We all have basically the same car, true...but a lot of different things can go wrong and give people the same symptoms. Likewise with the same problem giving different people different symptoms. I see a lot of people taking advice from other members that had simular problems....they heed that advice and it doesn't work.

Case in point, my car was bucking and hesitating under heavy throttle, above 3k RPMs. Everybody swore up and down it was the fuel pump or fuel filter. I knew that wasn't the problem...so I diagnosed my car (no CEL) and found my IMRC was dying. The IMRC was sending intermittent signals to the PCM and it was pulsing my injectors in an inconsistant manner. I replaced my IMRC and the problem never came back. Now typically someone would display those symptoms and everybody would tell them to replace their fuel pump and filter....which would have been a huge waste of money and would not have solved the problem.

Again, the members here are a great help, as we have seen just about every possible problem these cars could have. But don't rely on our opinions, error codes, or experience to give you all the answers. Code readers and experienced people are great assests....but there is always a big chance those could lead you in the wrong direction. The best way to avoid problems is to learn, study, and understand how your car works. Your own experience and knowledge can save you a lot of money.

Just a little FYI that might save you money in the future. :)
 

·
That link is NSFW
Joined
·
14,377 Posts
so your telling me my low voltage code isn't my alternator???? but seriously, very very well written.
 

·
Registered
Joined
·
10 Posts
Excellent post.

I almost did the same thing. I've had a CEL on my 99' V6 Cougar for a VERY long time. I finally have to take it in for emissions and decided to get it fixed. I brought it to AUTOZONE and they did the diag and it came back w/ the generic "o2" error. I read the forums and saw that a lot of people have issues w/ their O2 sensors, but I wasn't 100% sure.

So... I took the plunge and took it in and got it looked at professionally and it turns out that my "air intake tube" was completely thrashed open (I never saw it) and it was causing my codes. They replaced it and as soon as they were done reset me and blamo... CEL was gone!

So take this post to heart. Sure the 70/80 bucks is a pain... but I would've spent 140 on new O2 Sensors and it never would've been my problem and I'd of ended up at the shop anyhow to get it diag'd.
 

·
Registered
Joined
·
127 Posts
I fully agree that CELs are only a starting point. Unfortunately, my experience with dealer's service departments is often no better than the the pepboys approach. Anytime multiple codes appear you should be suspect that they are identifying the culprit. I have had more than a few experiences where the dealer mechanics didn't know as much as I did about the car or the problem. For example, I had a mechanic tell me he had to remove the intake manifold to replace the spark plug wires on a 2.5l cougar. I have asked for tests specified in the ford service manual, only to have the service manager tell me they didn't know what I was talking about and the only available diagnosis was an extremely expensive disassembly. I have sent my wife to have a warranted item fixed only for them to fix a half dozen other things before they finally did what I asked them to do in the first place. These were different dealerships by the way.

I have also found a dealership mechanic who knew his particular brand of vehicles like the back of his hand and usually knew the problem just from a description of the symptoms. Unfortunately, I know longer live around that dealership. I will still take my car to a dealership when it is under warrnaty or I am having a difficult time pinpointing the problem. I just listen to their recommendations with a skeptical ear. It seems nowadays I can't take my car into a dealership without the need for "induction service" or "injector service" along with the problem I wanted addressed in the first place. I go in for a warranty action and they find 500 dollars worth of "maintenance" they should do for me.

Today's cars run on interdependent electronics. The signal from one component initiates signals to the others they react and every error is noted. However, sometimes a slightly off signal can initiate errors in the other components. I have seen a slightly bad IACV cause a TPS and an EGR valve error code but none for the IACV. It still comes down to knowing the vehicle, how it's running and to a large degree where are the weak points in the design. That is why websites like these are so useful. By sharing our experiences we get a better understanding of our particular model, which points to the more likely causes of the problems owners face. I also can't stress enough to clean your engine hands on. When you learn where things are while it is working right, it gets a lot easier to spot something loose or broken when it is acting up. But just like the visual inspection seeks to narrow the possibilities, use the boards here to focus on an area, not as a diagnosis for your particular problem.
 

·
Registered
Joined
·
23 Posts
I was born and raised in saudi arabia, my dad tought everything there is to know about engines. I was replacing alternators and starters when i was in 4th GRADE!! Anyways over there the only place to get your car scanned was at the dealership and it was way overpriced! So i didn't know what the hell OBDII or DTC's were till I came to texas 3 years ago. (i knew what they were but never checked them) Basicly i was brought up the traditional way, diagnose by personal expierence and knowledge as well as elimination. I've noticed the people here think its "cool" or they know more about cars if they can say random numbers and letters put together and use all these acronyms! I'm sorry but for me getting under a car and all dirty and grimmy is manly, but when kids start saying all this random **** they've memorized off some forum or website they're not manly, they're the people that need to be walking around dressed in their fathers hand me down slacks and a tucked in shirt with a shinny stiff comb over! Oh yah, they should also have a protractor along with the pen case in the front pocket.

ANYWAY I've got a '99 cougar now and its giving me problem after problem (i'll post a new topic with all the issues cuz it'll be off this topic) but one of the problems i have is just like the one Fett has:

Fett said:
...my car was bucking and hesitating under heavy throttle, above 3k RPMs. Everybody swore up and down it was the fuel pump or fuel filter. I knew that wasn't the problem...so I diagnosed my car (no CEL) and found my IMRC was dying. The IMRC was sending intermittent signals to the PCM and it was pulsing my injectors in an inconsistant manner. I replaced my IMRC and the problem never came back. Now typically someone would display those symptoms and everybody would tell them to replace their fuel pump and filter....which would have been a huge waste of money and would not have solved the problem.
I got my IMRC replaced almost a year ago, then about 4 months ago i noticed that the plastic grommit was missing so the rod from the IMRC wasn't doing anything! So i got that piece and replaced it but now, starting from maybe two weeks ago I have an ENORMOUS loss of power. My golf cart accelerates faster! I just retrieved the codes(here we go :rolleyes: ) and i'm getting P9318. I looked that up and its: Battery voltage low (less than 10) I just replaced the alternator and battery almost a month ago. Also when i'm driving the battery light flickers on and off, sometimes stays on solid, and sometimes doesn't even come on. I'm about to go check all the wiring and do some voltage draw tests etc. anyone experienced this before and want to give me a heads up?
 
1 - 10 of 10 Posts
Status
Not open for further replies.
Top