I fixed my problem with codes 14 and 15... connected the factory wiring and the new wiring together directly instead of trying to use a butt connector. Worked adequately and I no longer have either code 14 or 15.

However, it seems that after that was taken care of, the car wants to throw me ANOTHER code... this time Code 41: EST Circuit failure - No distributor pulses. Plus, now the heater and A/C don't work at all (as in, they won't blow air at all). And again I'm clueless as to what to do.

I was going to check the EST wire itself, but I could not find it. It is supposedly a tan wire with a black stripe. I looked over near the passenger side firewall and strut tower (I've seen someone post a picture of it at that location on their car) and by the driver side firewall near the brake booster (Haynes manual suggests it would be near that). Neither place do I see a single tan wire with a black stripe. I did, however, see a green connector that was not hooked up to anything which had two green wires coming out of it near the passenger side firewall by the A/C Reciever-dryer, which was coming out of the large loom. That may be totally unrelated to this problem but I thought I'd mention it just in case.

Anyway, I think my solution to one problem may have caused another. Is it possible for the wiring of the CTS to cause a problem with the EST circuit? Would there be a problem if I may have wired the sensor harness wrong (like if I connected the yellow and black wires to the wrong side of the harness)? Any reason the heater and A/C would stop blowing air all of a sudden?

PLEASE HELP!

P.S. - By the way, if you looking at the engine from the front of your car, is the black wire from the CTS supposed to be the one closest to you, or the yellow wire?

 

Anyone?

 

You'll find the connector INSIDE one of your black wiring harnesses. Pull the harness open and work your way along it and you should be able to find it in one of the two location's you mentioned. The book also say's to check your MAP sensor connections, have you done that yet? Both vacuum and elec. connections. Also, check the elec. connections on the control module by the power brake booster.

 

Ok, I'll check that out. But what I wanted to know is if messing with the CTS wiring could have caused a problem with the EST?

This only started after I rewired the CTS.

 

I dug a little deeper into my manuals and discovered other problems related to code 41, here they are! 1. Cam sensor failed, or
circut fault. 2. Cylinder select error, or ignition module. 3. ECM wiring problem. Cam sensor was a new code for 1984 and cylinder select, ign. module was new in 1985. that's about all I have for you. Hope this will give you something else to check besides what I gave you before. good luck and keep us updated!

 

Hello Nate86,

Before things get a little confusing here on your code 41. Here is the code 41 troubleshooting chart from a 85 firebird GM service manual for the LG4 engine. Take a look at it and see if this will help you.

 

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Bout' time you showed yourself, Tricky! I was begining to think you crashed and burned!

 

I did for awhile, bad thunderstorm here wiped out some of my equipment for a day or so.

 

Thanks for the diagrams, Trickster!

I'm having a hard time understanding everything, but from what I can gather the cause could be a bad MAP sensor. Is this a correct assumption?

Do MAP sensors just go "bad" like that? I don't believe I have messed with the MAP sensor since I bought the car, unless I worked on it wihout realizing what it was.

When I check it, I start the car, remove the four wire distributor terminal and place a voltohmeter on terminal "a" and "b," correct? And then I remove the vacuum hose and check for a voltage drop of 1 volt or more? What then?

What should I do if the MAP sensor is bad? Do they sell replacements in auto parts stores?

Sorry for all the questions, but this stuff seems very complicated to me and I don't want to break something else trying to fix this code 41.

Thanks again!

 

You're welcome for the diagrams Nate86, just a couple of guestions here. Are you getting a code 12 along with the code 41 or just the code 41. Also, the two wire connector that you found. Are you sure it is two green wires and not a light green and a light blue wire? If it is the blue and green wires, it probably goes to the pressure cycling switch for the A/C control head and would explain why your heater and A/C doesn't work

 

I am positive that the connector has two green wires. Tomorrow I will take a picture of it so you can see what wires I am talking about exactly.

I don't know if I'm getting an "authentic" code 12 because I have been afraid to start the car and then jump the A and B ALDL terminals. Is this safe to do so I can check whether or not I'm getting a code 12 or no?

By the way, I reversed the CTS wiring today and now I have A/C and heat again. But the code 41 is still there.

 

You don't have to start the car to get your trouble codes. Just jumper pins "A" & "B" of the ALDL (ALCL in older cars) and turn the key to the "ON" position with the engine off. That's good to hear about the CTS wiring.

 

Yes, but doing it that way, wouldn't I always get a code 12 anyway (because the engine isn't running)?

EDIT: I mean I do get a code 12, but I thought I was supposed to recieve a code 12 even if I didn't have any other codes.

 

That is true, you will always get a code 12 with the engine turned off. That is a normal function, it means that the distributor is not putting out any reference pulses and it won't put out any if it isn't turning. It is when you don't get the code 12 with the engine off that you have to worry. If the engine is running you will not get a code 12. So try running the codes with engine turned off. BTW, jumpering the ALDL with the engine running is not recommended except on some carburated models and even then I have my doubts.

 

Alright, from what you have said, let me try to go over exactly what the car is doing and how it led up to that.

Currently, when I start the car, the SES light comes on for a very brief period (maybe 3-4 seconds) and then goes off. During normal driving it does not come on and I have verified it is not a time sensitive code by driving around town for 30 minutes (light did not come on the entire time). The light only comes on when I let the car sit for an extended period of time. If I start the car 20 minutes after turning it off from driving it, the light does not appear.

When I jump "B" and "A" terminals on the ALDL, it flashes the code 12 three times, then flashes code 41 three times, and the repeats code 12. I'm not sure if this means I am getting a code 12 or not but it definately flashes code 12 so I know that it has entered diagnostic mode.

I know symptoms of a code 41 is poor fuel economy, poor performance and a sulfur type smell out of the exhaust. Right now, I am experiencing two of the three symptoms describe. The car has an awful gas smell coming out of the exhaust and the car seems to be chugging down gas fairly quickly (I drive about 25 miles today and the car is down to half a tank after previously being at a little above the 3/4 mark). As far as performance, I can't seem to tell a difference. It idles like it normally does, and it does stall occasionally (mostly when I am in reverse) but that's something it has always done since I have been driving the car).

The code first appeared after I rewired the CTS harness with a new one (the factory one was broken) and ever since then it has been appearing. I don't know if it has anything to do with the CTS or not, but I do know I did NOT have a code 41 before I fixed it. I did have a code 14 and 15, but they have not reappeared since I rewired the sensor.

A little information about the car:

1985 Pontiac Trans Am
5.0L LG4
TH700R4 Automatic
Everything is stock except for the air filter (K&N) and the exhaust (no pipe from the cat--basically an open exhaust after the catalytic converter)

I hope that helps a little bit. Sorry for the length.

 

Not a problem, as you have noticed the diagram includes a picture of the HEI module (ignition) and the pick-up coil. As mentioned in the diagram, code 41 alone means the problem is intermittent and you have verified that with what you have mentioned in your post. The ses light will come on momentarily when you first turn the key until the engine starts and the light will go out. This is normal. If would like, I will post the info in the chart 34 that is mentioned in the diagram. It is the chart for the MAP sensor.

 

Ok... so what you're saying is I really don't have much to worry about?

I'd appreciate it if you could that chart as well.

Thanks again for all the help Trickster! I greatly appreciate it.

 

You out there, Trickster?

 

Hey Nate,

Yeah I'm out here barely, had nasty run in with a nest of yellow jackets who didn't appreciate me intruding on their territory. I will get that chart up for you in a minute.

 

Two words for those fuggers... Starter Fluid. Instant Death.

 

By my poor antiquated math skills Red Devil, that is four words but who's counting. Ah, the smell of Napalm in the morning air. Any way, back to Nates problem. Here is that chart I promised you Nate.

P.S. I couldn't use the starter fluid Red, they were in the carport and I don't think my other half would appreciate me burning the place down for that.

 

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Musta missed the periods. The instand death is wht the little fuggers get.

 

I resorted to chemical warfare, bean gas.

 

Thanks again Trickster. Sorry to hear about your "close encounter" with those yellow jackets. Ouch.

 

Bean gas? Is that the same as Mexican Methane?

 

Yep and with a secret enhanced additive known as extra spicy Thai food designed to increase the maximum output for increased efficiency.

 

Little fugger's don't stand a chance! At least your downwind from Indiana! I here their looking for a few good winged mech's in the middle east! pay's good and there's a signing bonus! They have high Oct. gas over there you know? but the roads have a few crater's in them!

 

Increase "maximum output for increased efficiency"....

->

 

Tire's go flat?

 

:werd:

 

Bringing an old post back from the dead...

I'm still getting a code 41. I know it is an intermittent code, because it only stays on for about ten seconds after I start the car, and then goes away until I let it sit for a good four to five hours.

It's been a while but I finally got around to nabbing an "authentic" CTS harness off of a junkyard 305 T/A. I took the vehicle speed sensor off the CTS itself and soldered up the real CTS harness and wiring to the stock wiring of the car.

Started up the car right after finishing the job, and the code wasn't there. I was getting pretty happy at this point because it seemed like I finally stopped this stupid light from coming on. However, just to make sure, I started her up again and low and behold the light comes on AGAIN. Checked it with a paper clip and it's still the same retarded code 41 as always.

I'm completely out of ideas now. If anyone else has any advice for me, let me know because I'm stumped.