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Discussion Starter #1 (Edited)
Hi guys, I recently posted I needed help installing my cold air intake and all the leads for it which I got done thanks to everyone here.



So again I bought the car In I believe in 07 had the engine torn apart by a mechanic to find the vin derivative to prove its low miles compared to actual odometer miles, and he took off on me, and it was garaged up until 2 years ago when a mechanic helped me put it back together. When I drove it home it had no Mass air Sensor or anything connected for an air intake and the car seamed like it was in limp mode slipping and it didn't have any problems when I bought it and drove it last which was a 5 hour drive. So I connected all the air intake things and still the same thing.



I used a Snap On Solus Pro ODB1 adapter and pulled these codes, and I also deleted and tried again and these are all the codes that are coming up, which just seem ridiculous on how many there are. Also there seems to be steam coming from the trans dip stick due to the over work of the trans in limp mode.




11 Malfunction Indicator Lamp Fault

16 Low Resolution Pulse Failure

18 Mass Air Flow System Failure

25 Manifold Temperature Too High

26 EVAP Purge Control Circuit Fault

27 EGR Electrical Fault

32 EGR System Problem

41 Mass Air Flow System Failure

42 EGR System Problem

43 ESC Module Or Sensor Circuit Problem

44 Left Oxygen Sensor Too Lean

48 Mass Air Flow System Failure

52 Oil Temperature Sensor Or Circuit Too Low

55 Fuel System Lean

61 A/C Compressor Fault

62 Oil Temperature Sensor Or Circuit Too High

63 Right Oxygen Sensor Or Circuit

64 Right Oxygen Sensor Too Lean

65 Right Oxygen Sensor Too Rich

66 A/C Pressure Sensor/ Circuit Problem

67 A/C Pressure Sensor Circuit Fault

68 A/C Relay Shorted

69 A/C Clutch Circuit Open

83 Torque Converter Quad Driver Module

84 3-2 Downshift Feedback Fault

85 TCC Stuck On

I'm pretty good at diagnosing issues but I don't know about this one, is something unplugged, did the computer go bad, idk? Any help would be great.
 

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I'm pretty good at diagnosing issues but I don't know about this one, is something unplugged, did the computer go bad, idk? Any help would be great.
Maybe some one with more patience can help but I have too many simple questions.


Does your check engine (MIL) light work?
Is your MAF wired correct?
Is your EVAP connected?
Is your EGR connected?
Are your O2s connected?
Is your A/C charged?


A total guess would be harness damage.
Transmission and O2s in one harness and oil, MAF, and temp sensors are the engine harness.


These cars require work not guessing so get out the ohm meter and see if you have the right plug end going to the correct PCM pin.


If you do not have a FSM try:

Goldswagon
 

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I assume you had to lengthen the maf plug and a few more with that intake. Have you probed anything?

Sent from my SM-G965U using Tapatalk
 

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Discussion Starter #4
To Z09B4U

Does your check engine (MIL) light work?
Yes



Is your MAF wired correct?
It just has an added extension piece that was included with the CAI.



Is your EVAP connected?
Is your EGR connected?
Are your O2s connected?
When the first guy ripped up the engine I was with him, he took off everything to see the vin derivative and since everything was torn apart I bought a new double roller timing chain, opti-spark, MSD Distributor, custom headers and he got to the headers and chain and stopped there.


He had 2 engine mounts removed and the engine raised up, and basically all the passenger fender wall that holds the fuse box and forgot what else off plus the upper intake, he threw out all of my air intake stuff including the MAF, (Which I have no idea why) but I don't remember wiring being cut or damaged. And wiring is my worst nightmare.



I do remember all of these these items being connected when the recent mechanic put it back together. I don't see any loose wires or connections in the engine bay besides my air pump that's been deleted.







Is your A/C charged?
I just wanted to list all my codes, but this is the least of my concerns.

A total guess would be harness damage.


Transmission and O2s in one harness and oil, MAF, and temp sensors are the engine harness.
Again not great at wiring issues I'll take a look under the car.



See if you have the right plug end going to the correct PCM pin.
What do you mean by right plug end going to the correct PCM pin? Are there incorrect ways to plug it in where it still fits? This could be it if so.
 

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What do you mean by right plug end going to the correct PCM pin? Are there incorrect ways to plug it in where it still fits? This could be it if so.

Connectors should fit only one way. There should not be any connector on a stock harness that could reach a wrong connector.


Again not great at wiring issues I'll take a look under the car.

There are many ways to trouble shoot wiring. One is to check for voltage at the correct pin in a connector. When someone says they are not good with wiring I always suggest ohm meter checks from one end of the wire to the other with both ends disconnected from the car. As you are getting some codes that suggest directly or indirectly wires shorted together you would also check if wires were some how making a connection that should not.


One example would be a temperature sensor circuit. From the PCM you find a good wire path to the sensor plug. But you may also find that this wire is (wrongly) connecting a ground or power pin.(this is a example not a exact test for your car).


You are asking this forum to comment on trouble codes that are listed in the factory service manual.(FSM) Each code has one to ten or more pages dedicated to trouble shooting diagnostic charts. I am sure most of us like to help, but if you do not have a FSM it is a lot to ask of us to guide you through pages of check lists when you should own the FSM and do the checks first.



Basic checks would include checking each connector for correct signals at each plug. Does it get the +12volt, +5v, or ground it needs? Does it sent a good signal back to the PCM or is that wire shorted to power or ground.
 

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DTC 11


"If other DCTs are displayed along with DCT 11, repair other DCTs first, then restart at the beginning of this chart"


Does the Snap On Solus Pro do live data on the LT1? You could see if the data is maxed out or zero on some of the sensors. You would also know under what condition the OPTI signal is dropping out.
 

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Looking over your DCT codes I think there is a common theme.


You may not have a good ground to the four grounds on the PCM. So you should start with a common problem. The grounds that bolt to the drivers side head. It is the stud by the ignition coil and the ICM. The ring terminals need to be clean as well as the stud and metal in contact with it.


Several of your DTCs contradict each other so I think a intermittent issue with ground or power to the PCM would be a good place to start.
 

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Discussion Starter #8
So I haven’t been able to get back to the car till the other day, which is making this process so much longer unfortunately. I would like to get this fixed this summer.

You may not have a good ground to the four grounds on the PCM. So you should start with a common problem. The grounds that bolt to the drivers side head. It is the stud by the ignition coil and the ICM. The ring terminals need to be clean as well as the stud and metal in contact with it.
1D39A544-BC62-45C2-9DDB-7EBEF20643D0.jpeg


Are you referring to the large rusted bolt connected to the harness. Does it look intact or do I need to take it off, sand the area and clean it?

If this is not the fix what’s next?

I don’t know how to read live data If my snap-on does do it.
 

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The bolt holds the ground wire terminals tight against the block. The wires tend to fatigue and break where they are crimped to the connectors.

Never let fear or ignorance drive your decisionmaking. If you don't like wiring, figure it out, buy the right tools and get good at it. If you don't know how to use a tool, go find and read the instructions, then play with it until you figure it out. Read and understand the factory service manuals.

If I was in your shoes, I would do a fault tree analysis (look it up). Just like lots of small branches are connected to one big branch, all your error codes are likely connected to a few common circuits. Figure out which circuits they are, why they are not working, and when you fix them, you'll fix all the faults.
 

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all your error codes are likely connected to a few common circuits
Not all but most of the codes refer to circuits that use these ground terminals.

If you don't like wiring, figure it out, buy the right tools and get good at it. If you don't know how to use a tool, go find and read the instructions, then play with it until you figure it out.
When someone says they are not good with wiring I always suggest ohm meter checks from one end of the wire to the other with both ends disconnected from the car.
You may find a damaged or broken wire but a meter will find things that no human can see.

From the factory diagram and a look at my 94 that is g104 normally It is a stud. Since some one used a bolt which twisted the harness into the ignition coil I would carefully remove the tape and check for wire damage or a wire broken off one of the three ring connectors. The ring terminals need to be clean as well as the bolt and metal in contact with it. The ring terminals do not need sandpaper, try a little WD40 and a paper towel.

If you want to use a bolt instead of the factory stud the bolt needs to be clean. A new one would be best. So bolt head, ring terminals, clean(new) washer, and ICM bracket get bolted to the head.. make sure the wires are not touching the coil. The ground wires should not be taking the weight of the harness or it may break the wires where you can not see.

If this is not the fix what’s next?
Read and understand the factory service manuals.
If I was in your shoes, I would do a fault tree analysis (look it up).
You are asking this forum to comment on trouble codes that are listed in the factory service manual.(FSM) Each code has one to ten or more pages dedicated to trouble shooting diagnostic charts. I am sure most of us like to help, but if you do not have a FSM it is a lot to ask of us to guide you through pages of check lists when you should own the FSM and do the checks first.
If it was my car I would use a ohm meter to check from the PCM,MAF, and O2 sensors to the ground on the head. Maybe someone you know could help. Or find a good shop.

There are a lot of possible problems with that many codes.

52 Oil Temperature Sensor Or Circuit Too Low
This is not a code for a OBD1 LT1. It is not in the service manual. Check your scanner settings. It may be a communication issue.
 

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52 Oil Temperature Sensor Or Circuit Too Low
This is not a code for a OBD1 LT1. It is not in the service manual. Check your scanner settings. It may be a communication issue.
This IS a code for OBD1 LT1 … Corvettes, ONLY, as only Corvettes used an oil temp sensor.
Hmmm …
 

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This IS a code for OBD1 LT1 … Corvettes, ONLY, as only Corvettes used an oil temp sensor.
Hmmm …
If you search code+52 you will find it has been reported before. Common factors are O2 problems and fuel trim issues. Same as this.

It could be a PCM quirk due to power issues or grounding (G104). Bad diodes in the alternator is a wild guess. I can not find a thread with a solution so I doubt the answer is to replace the PCM as a expensive repair would be mentioned.
 

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Discussion Starter #13
This is my PCM currently. Is it a correct PCM to a 1996 Impala?

Again my Impala is a 95 with a 96 full drivetrain and floor shifter, but the gauge cluster is still out of a 95 and digital.

I’ve also read if a 96 motor goes in a 95, the knock sensors need to be out of a 95. If the car ran fine before the tear down, would that conclude that the knock sensors were changed?


8D91E59C-589F-448E-99DE-447FEA8AAE90.jpeg
 

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16214399 is my PCM currently. Is it a correct PCM to a 1996 Impala?
16214399 is for any '96 LT1 or L99, not specific to any version.
Again my Impala is a 95 with a 96 full drivetrain and floor shifter, but the gauge cluster is still out of a 95 and digital.
Any idea what year is your main wiring harness? At least as important as your other questions.
I’ve also read if a 96 motor goes in a 95, the knock sensors need to be out of a 95. If the car ran fine before the tear down, would that conclude that the knock sensors were changed?
There are OBD1 knock sensors and OBD2 knock sensors. Either the knock sensors must match the pcm, or modifications need to be made.
 

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I used a Snap On Solus Pro ODB1 adapter and pulled these codes
And gave us a list of OBD1 codes.
This is my PCM currently. Is it a correct PCM to a 1996 Impala?
Again my Impala is a 95 with a 96 full drivetrain and floor shifter, but the gauge cluster is still out of a 95 and digital.
The name of this thread is:
1995 Impala I believe is in Limp mode

And there is NO "Again my Impala is a 95 with a 96 full drivetrain" You NEVER mentioned this in this thread

You have given us OBD1 codes and not OBDII P0 codes and mislead us with 95 impala.
 

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Discussion Starter #16 (Edited)
And there is NO "Again my Impala is a 95 with a 96 full drivetrain" You NEVER mentioned this in this thread

You have given us OBD1 codes and not OBDII P0 codes and mislead us with 95 impala.
It’s been 13 years since all this started and I lost the title of the car that had the engine with 83k on it. I still had a picture of the vin derivative on the motor, and I looked up the year of the vehicle threw that picture and looked up the PCM also. This was all yesterday.

The connection under my dash is an OBD-1, it is a 95 car still. There wouldn’t be an OBD-2 connection correct? Also the Snap-on did read these codes.

The car drove fine before being torn apart.

I did not put the motor, trans or anything in this car so I have no idea what kind of wiring harness is in it.
 

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Discussion Starter #17
I cleaned the bolt and looked threw the harness couldn’t find anything wrong. I’m stumped and have no idea on what to do next.
 
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