Someone Please Help- 97 Blazer

:banghead:

Ok..here goes..this has been an on going saga. My check engine light was on for a long time...I finally had to get it fixed because my emissions testing was due. Well, I wound up needing a new computer. The new one is put in and the engine light goes off. The place that fixed my Blazer did the emissions..I was only able to pick my blazer up after they were gone for the evening. I get a ride to get my truck, get in, turn the key and guess what? The engine light is on again.:banghead:
So , I go back and they tell me it's an o2 sensor. I have the sensor changed and the light is still on...I have it read again and it says 4 o2 sensors..How can it be 4 when one is brand new?!! It would only be 3 if it was all the sensors. I was told it my be the catalytic converter. I've already had 2 of those put in, in the past year and a half. The guy at the shop said the cat doesn't have a code. Is that right? I thought last time it was the cat, a code for it came up. And...would a vacuum leak make the o2 sensors throw codes?? I hope I explained this well enough and sorry it was a short story...Any help would be great...Thanks in advance...

It sounds like you are getting the old run around.
I would take it back tell them to fix it on there dime or give you your money back.

What were the code no. for the o2 sensors?
4-02 sensors do not go bad all at one time.
If the cat is not working right you should get a P0420-P0430 cat code.
But many other things will cause a cat code or 02 sensor code.
How is the tune up or engine running?
Also remember a 97 is a bad year on ign switches.
MT

Thanks for the quick response...I am not sure what the o2 sensor codes were but I was told it was the 4 sensors from a place different from the original one that did the computer work...But the fact that original place said the cat doesn't have a code, makes me worried that they really didn't know what they were doing and messed something up...They did say the new computer had a warranty so I will be going back to them tomorrow with the 2 cat codes that were given in the previous post and I will have them check it. If they cannot get to the bottom of this, I will insist on another computer... :disappoin :banghead: :runaround: Thanks again...

It is EXTREMELY rare for a PCM to fail. A far more common failure is the technicians ability to follow diagnostic procedures. You're in a tough spot now, and it might be in your best interest to get your old PCM re-installed. Better hurry though, some shops send them back for core credit very quickly. Then take the vehicle to a competant technician and get a second opinion. Or, post the DTC's here and we can help you diagnose it.

Usually when the EEM (Computer) goes, the engine won't run. Very similar symptoms to a bad iginition switch on a '97; no codes, engine cranks but won't start. no spark. I had both go on mine, so I'd have to agree; you've been taken by a guesstechnician. Guess which part is bad, and change it until it's fixed.

You'll probably have to go elsewhere for the correct diagnosis. Knuckleheads who do the type of work you paid for will never admit doing something wrong.

Well, when I originally brought it in for the 'engine light' they told me when they checked it, that a lot of different codes were showing. And that if every code that it showed was the problem, the truck would not be running..It actually ran ok... They also said that every time they replaced something, different codes were popping up...They had the truck for 2 weeks trying to figure it out...They seemed to be as frustrated as I was...I thought they knew what they were doing. And I guess being a female, I really had no idea what they were talking about even when they tried to explain as best they could...Well, after all said and done it cost me $914 plus I gave the guy a $30 tip... I guess I was taken huh?? The chances of getting the old computer back are slim...I will go back and tell them they need to fix this and that I am not paying another penny....And that the CAT does have codes..(one guy told me the CAT doesn't have a code).

Thanks everyone for all your help...It is much appreciated.

It is EXTREMELY rare for a PCM to fail. A far more common failure is the technicians ability to follow diagnostic procedures. You're in a tough spot now, and it might be in your best interest to get your old PCM re-installed. Better hurry though, some shops send them back for core credit very quickly. Then take the vehicle to a competant technician and get a second opinion. Or, post the DTC's here and we can help you diagnose it.:iagree:

Wow, I think you need to find another garage. I would either get your old computer back or a refund. 02 sensors and many other sensors can be checked with a multi-meter to determine if they are defective or not. It sounds like they don't know what they are doing and are just throwing parts at it at your expense. Could you pull your codes and post them here? Advanced will do it for free.

Yes. I will try and get the codes and post them later on today...Wow, thanks everyone for all your input. :)

Ok...I went to the repair shop today...Here are codes he gave me...

PO 135
PO 141
PO 147
PO 155
PO 1406 :shakehead :frown:

P0135- Heated O2 Sensor, Heater Circuit Sensor 1.

P0141- Heated O2 Sensor, Heater Circuit Sensor 2.

P0147- Heated O2 Sensor, Heater Circuit Bank 1, Sensor 3.

P0155- Heated O2 Sensor, Heater Circuit Bank 2, Sensor 1.

P1406- EGR Valve Pintle Position Circuit. Looks like the EGR valve can be stuck in one position or the wiring is damaged.

Can it be possible that all those things are wrong and the truck still be running?...It actually runs fine. Smooth start up, smooth idle & ok gas mileage. You are probably wondering why then, am I so concerned with the "engine light" being on...I really wouldn't care but I am tired of seeing it on when I just spent $914 to have the problem fixed...and it just shouldn't be on...and maybe even though the truck runs good and the gas mileage is ok, maybe it can be better....So, the saga continues.........................

Can it be possible that all those things are wrong and the truck still be running?...It actually runs fine. Smooth start up, smooth idle & decent gas mileage.

It would run but I would think that it would be running really rich with all of the 02 errors, and the screwed up egr valve. How is your gas milage? Maybe your EGR is stuck shut? I have had them stick before but the car would hardly even run.

The truck runs fine...Smooth start up, smooth idle and the gas mileage is ok. At least I think so...I am not sure how big my gas tank is..maybe 16 gallons? But every time I fill it, I reset the tripometer and I get at least 230-250 miles on that tank full...I think that"s ok...what do you think?

Well thats only like 16mpg, Shouldnt you be getting almost 20?

The EGR fault is most likely due to the O2 sensor problems. The PCM can't recognize a change in O2 voltage when the EGR valve is commanded to open. With all of those O2 sensor heater problems, I'd look for one common problem: ie. a blown fuse, poor connection to PCM, a poor ground etc. Very unlikely all heaters would be faulty, and even less likely that the PCM is faulty.

Wow...I just want my truck to be fixed...what type of repair shop do you think I need to take it too??
I guess I was really taken because the new pcm is showing all different codes just like the old one was...So I guess you are right, it is something other than the pcm...I will never go back to that shop....

Ok...I went to the repair shop today...Here are codes he gave me...

PO 135
PO 141
PO 147
PO 155
PO 1406 :snakehead :frown:


As Chris posted the first 4 codes are 02 sensor heater circuit problems.
Not actually 02 sensor problems.
They use a heater circuit to help on warm up of the 02 sensors.
If all 4 have the same heater circuit problem go for 12 volt power check on the heater circuit.
Like fuse first.
Start with the 02 sensor heater fuse or wiring.

On the 1406 code you will need a engine capable scanner to check the egr valve pintle position sensor and egr valve operation.

All of the codes will need fixed before the engine light will go out.

Ok..so my father goes to that repair shop today and tells the owner that he needs to fix my truck or refund me at least half of my $914. Well, I have to bring it back on Monday...so until then thanks for everything and I am going to print some of the things you all said and show it to him....I do wish one of you lived in Coweta County, GA so maybe you could get this thing straightened out for me....:) I will let you know what happens..................................

Good luck.
And let us know how it goes.
MT

Hi...I just wanted to leave an update.....I brought my truck back in on Monday, they couldn't get to it...I also found out that the guy that actually did all the work on my truck just up and quit...The owner was so apologetic about everything that has been going on....They did however, hook it up to see what codes it was throwing out this time...and guess what??? My truck's computer was not communicating again!!!! That was the original problem and the reason that guy told me I needed a new computer...Anyway, the owner and the other mechanic said they will get to the bottom of this and thanked me for being so patient. Soooo, I will bring it back next Monday and let everyone know what happens........................................... .............................................

Good luck
And we hope they take care of it for you on there dime.
You need to be nice but at the same time be firm with them.
MT

It sounds like they're being nice, but their actions say something else.
"OH, we're so sorry, this is awful, we'll get to the bottom of it.... bring it back next week." ??? Seems to me if they were really upset about it, they would have have apologized and put someone one it right then, or first thing in the morning. As MT said, be nice, but be firm. Don't let them jerk you around.