jndnaps

TPS and ICM Question

Recommended Posts

I just want to say however that any leak bad enough to cause this high idle probably would set a lean code, but maybe it isn't bad enough to do so.  Do you have P0171 and or P0174 codes as history?


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

14 minutes ago, BodybyFisher said:

It definitely could be the intake manifold gaskets, no question about it.  Especially given your description of it being intermittent at times.  A crack would be constant.

Personally, removing the intake to me is a little intimidating the first time you do it, but not hard at all.

I will give you my cell number and we can talk though the job together.   I will give you a step by step with tools required. 

Let me know

Thanks! I watched a few videos on removal and I would need to buy the fuel line tool. I get intimidated very easy. I thought I was gonna have a heart attack doing the throttle body removal. This is way worse. LOL.. The problem is now constant. The next choice, if it's cracked, do I get a new one, or try one from the junkyard? There are plenty of these cars in the junkyard. HA! Now that I mention the junkyard, I may just go there and take one off there first just for practice. It'll cost $3.00 to get in, but that's it if I screw up. LOL.. 


CaddySig_zps68ef241b.jpg

Share this post


Link to post
Share on other sites
21 minutes ago, BodybyFisher said:

I just want to say however that any leak bad enough to cause this high idle probably would set a lean code, but maybe it isn't bad enough to do so.  Do you have P0171 and or P0174 codes as history?

Nope! Don't have those. The shop did a video of the smoke test and there was a lot of smoke coming out at both ends. Also, the MAF if bad. Gotta replace that too. 


CaddySig_zps68ef241b.jpg

Share this post


Link to post
Share on other sites

It may not be the manifold being cracked.  It wouldn't have started out intermittant in my opinion.  

You may be getting a bad leak from the anti-backfire valve at the end of the intake on the passenger side of the intake.

But I go back to there should be lean codes with a 4000 rpm idle 


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

With no lean codes. I am not optimistic that you are going to find bad intake gaskets or a bad anti backfire valve that is referred to as Blow by Valve above. The PCM is very sensitive to vacuum leaks that would cause your high idle of 4000 RPM. That you do not have lean codes to me is suspect. Do not waste your time at this point messing with the intake. Let me and Rock think about this for a bit. I need to look at the p1634 code to see what impact that will have.


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites
10 minutes ago, BodybyFisher said:

It may not be the manifold being cracked.  It wouldn't have started out intermittant in my opinion.  

You may be getting a bad leak from the anti-backfire valve at the end of the intake on the passenger side of the intake.

But I go back to there should be lean codes with a 4000 rpm idle 

 

3 minutes ago, BodybyFisher said:

With no lean codes. I am not optimistic that you are going to find bad intake gaskets or a bad anti backfire valve that is referred to as Blow by Valve above. The PCM is very sensitive to vacuum leaks that would cause your high idle of 4000 RPM. That you do not have lean codes to me is suspect. Do not waste your time at this point messing with the intake. Let me and Rock think about this for a bit. I need to look at the p1634 code to see what impact that will have.

OK, Thanks! The guy mentioned that there was also an electrical problem. That's the P1634. I don't remember the numbers, but he said something like the current was low and he said it should be at a certain number, but it wasn't. I just don't remember what the numbers were.  


CaddySig_zps68ef241b.jpg

Share this post


Link to post
Share on other sites

In addition I am not sure how it was determined that you have a bad MAF valve that would set a code also I would be very suspect of mechanics playing parts replacement the codes are there for a reason let us think about this


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

Please pull all p or powertrain codes both history and current and post them here thanks


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites
5 minutes ago, BodybyFisher said:

Please pull all p or powertrain codes both history and current and post them here thanks

Just re checked.. Current codes are: P1634 - P2511 - C0073

History are:  P1599 - P1644 - P1552 - P2510 - P2515 - P1558 - RS0061 - IR2255 - 


CaddySig_zps68ef241b.jpg

Share this post


Link to post
Share on other sites
36 minutes ago, BodybyFisher said:

In addition I am not sure how it was determined that you have a bad MAF valve that would set a code also I would be very suspect of mechanics playing parts replacement the codes are there for a reason let us think about this

I do remember there was a P0101 code, but it's not there anymore at all. Also, if I unplug it the car stays the same. I thought they usually stall out when unplugged. But again, there isn't a current or history code for that anymore. 

 


CaddySig_zps68ef241b.jpg

Share this post


Link to post
Share on other sites
37 minutes ago, jndnaps said:

Just re checked.. Current codes are: P1634 - P2511 - C0073

History are:  P1599 - P1644 - P1552 - P2510 - P2515 - P1558 - RS0061 - IR2255 - 

Do me a favor, P2511 is actually B2511 correct?

Same with P2510, P2515  <<<< these are B codes correct?


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites
53 minutes ago, BodybyFisher said:

Do me a favor, P2511 is actually B2511 correct?

Same with P2510, P2515  <<<< these are B codes correct?

Yeah, I think they are. When I check codes it says IP2510 - IP2511 - IP2515. But the steering wheel controls are messed up so they gotta be B.. Never can figure all these codes out. Like the RS0061 - IR2255.  


CaddySig_zps68ef241b.jpg

Share this post


Link to post
Share on other sites

I would hold off on the MAF with no code.


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

The RS 0061 is the left rear height position sensor.  IIRC. 

I also think if you had intake leaks on both sides you would for sure have lean codes. So I am skeptical there.

If the intake was cracked it may vary the leak as it may open as the engine gets warmed up.

Let me do some more research on that 1634 code. I would not have them touch anything unless you know for sure that they have a proper diagnosis.  Otherwise it is just wasting money and opening up more can of worms. 

 Do you have a multimeter? Need to find the pinouts that pertain to that and verify if it is a wire or a pcm issue.

Ok so just off the top. 

Pin 19(PINK) at PCM goes to the underhood fuse panel. 10 amp fuse. labeled ign 1. 

Start easy. 

1. Replace the fuse. Dont care if it is blown or not. Check and report condition of pins.

2. If there is any corrosion that box needs to be pulled and closely inspected.

3. Disconnect battery. Pull fuse, ohm the pink wire from the fuse to the pcm plug pin 19. 

Report 

4. For a good reference touch the 2 leads together on the multimeter and that number would be your 0. 

If you are not comfortable with this then you need to have someone experienced do this


GM FAN FOREVER

Nice, clean, luxury= fine automobile

Share this post


Link to post
Share on other sites

P1634

CIRCUIT DESCRIPTION

The PCM is powered with 5 power feeds. Two of these feeds are from the battery, the other three are from the ignition switch and are called Ignition 1, Ignition Supplement and Ignition 0. Ignition 1 and Ignition Supplement are powered any time the key is in the CRANK, RUN or ACC positions. Ignition 0 is powered in ALL key positions except LOCK and CRANK. This diagnostic test is used to monitor the voltages received by the PCM at connector C1 terminals 18 and 19. When the engine is running, the PCM will compare the Ignition 1 voltage it receives at connector C1 terminal 19 to the Ignition 0 voltage it receives at connector C1 terminal 18. If the Ignition 1 and Ignition 0 voltages are more than 2 volts different for 5 seconds, DTC P1634 will set.

CONDITIONS FOR RUNNING THE DTC

Engine running

CONDITIONS FOR SETTING THE DTC

Voltage difference between Ignition 1 (PCM C1-19) and Ignition 0 (PCM C1-18) inputs greater than 2 volts for 5 seconds.

ACTION TAKEN WHEN THE DTC SETS

The PCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.

The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC

The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.

A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission retated diagnostic test.

PCM battery voltage is interrupted.

Using a Scan tool.

DIAGNOSTIC AIDS

If this DTC is intermittent check terminal contact at the PCM and the condition of the CKT 639 splice for an intermittent open condition.

A short to unswitched battery voltage on the Ignition 11 Ignition Supplement circuit will set this DTC. Symptoms associated with this condition include the inability to shut the engine OFF using the ignition switch.

If the Ignition 0 to the PCM is lost the vehicle will still run but some outputs may not function, if the Ignition 1 voltage is lost or goes below 5.5 volts the vehicle will not run but DTC P1634 should set.

*******************

I am doing more research, will come back today


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

Analysis:

Ignition 1 and Ignition Supplement are powered any time the key is in the CRANK, RUN or ACC positions. Ignition 0 is powered in ALL key positions except LOCK and CRANK

So, Ignition 0 and Ignition 1, are powered when the key is in RUN, that is when the test is run to determine that the voltage is within 2 volts OR....P1634 is set.

Tasks > 1) determine where Ignition 0 and Ignition 1 obtain their voltage (they get it from 2 different fuses), 2) test the voltage on Ignition 0 (terminal 18) verses the voltage on Ignition 1 (terminal 19).   Obviously without testing for voltage we know that it is different because the P1634 is set. 

>>>>>>>>>Test the voltage at the fuses at IGN 0 (ENG) and PCM (IGN) and report back <<<<<<<<   Once you tell us the voltages we will know more.   (my guess is.... that you will find the same voltage at the fuses, but lets see)

I have read elsewhere that P1634 is like a 'safe mode' of the PCM  

Rock's advice of replacing the fuse is good but test voltages at the fuses first.   You can use your volt meter when the engine is running to test the voltage (put the voltmeter on the lowest scale that covers 12 volts) by touching the contact points on the fuse.   Report back what you find in voltage when the engine is running..

I would do these tests BEFORE messing with intake gaskets and cracked or leaking intakes, P codes MUST be eliminated first.

 

P16340001.jpg


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

if you look at the top of this fuse, you can see that there are test points to test for voltage, THAT is where you want to test, put your black lead on battery ground the red lead on each side of the fuse, voltage at both points should be the same.  Record the voltage on each fuse and report back here

 

iu.jpg


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

Ok, I have done some research.   There may be a misprint in the FSM, I am going to try secondary sources.  There is a confusion in CKT (circuit) 639 and CKT 539, with a possible misprint I am looking into it further

In the print below, they show CKT 639 feeding the ICM directly using a 20 amp fuse (I believe this fuse is called DISTR not PCM (IGN)) I am thinking that they have this circuit mis-labled as 639 and it should be 539.   If you look above you notice CKT 639 feeding the PCM at 2 locations (C1-37 & C2-19).  This may or may not be an issue but we need to proceed like it is an issue.  Besides testing for voltage at the 2 points I spoke about in my prior posting, test for power at the DISTR fuse, with the engine idling.

As you can see, if this circuit has problems, it feeds the ignition circuit.  I still need to find out what the wire that breaks out at S124 and connects at C2-19 on the PCM controls, I need a scan like the one below showing the PCM circuitry off C2-19.  

High resistance at S124 may be hurting the voltage supply to C2-19 driving the PCM crazy.   When you test for voltage at the PCM (IGN) fuse we will know more. 

I am going to the library to get into Alldata and see what they have

Let me know what you find.  Have patience

PCM Power0001.jpg


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

This is on the right track for sure.

There is a specific reason I said to replace the fuse. That is because of fatigue. I mention that because I have on multiple occasions had a fuse that tested good but the element was broken off a leg and although testing good on both sides The voltage will be present but not consistent, and worse under load.

I had a picture of a fuse with the issue but I would have to find it. Looked normal and tested good but the element was just touching the leg


GM FAN FOREVER

Nice, clean, luxury= fine automobile

Share this post


Link to post
Share on other sites
6 minutes ago, rockfangd said:

This is on the right track for sure.

There is a specific reason I said to replace the fuse. That is because of fatigue. I mention that because I have on multiple occasions had a fuse that tested good but the element was broken off a leg and although testing good on both sides The voltage will be present but not consistent, and worse under load.

I had a picture of a fuse with the issue but I would have to find it. Looked normal and tested good but the element was just touching the leg

I just saw this exact same thing on a FB engine group.  The fuse looked good but the leg was broken.


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

last one I had was a freightliner and the Transmission module kept dropping out. All fuses tested good. 

When plug to TCM was unplugged wire tested good. When plugged in it lacked about 4 volts. So rather than 12 it had 8.

That fuse caused a tow bill because when the Transmission module goes down the bus goes nowhere. 


GM FAN FOREVER

Nice, clean, luxury= fine automobile

Share this post


Link to post
Share on other sites
On 10/15/2018 at 10:10 PM, rockfangd said:

The RS 0061 is the left rear height position sensor.  IIRC. 

I also think if you had intake leaks on both sides you would for sure have lean codes. So I am skeptical there.

If the intake was cracked it may vary the leak as it may open as the engine gets warmed up.

Let me do some more research on that 1634 code. I would not have them touch anything unless you know for sure that they have a proper diagnosis.  Otherwise it is just wasting money and opening up more can of worms. 

 Do you have a multimeter? Need to find the pinouts that pertain to that and verify if it is a wire or a pcm issue.

Ok so just off the top. 

Pin 19(PINK) at PCM goes to the underhood fuse panel. 10 amp fuse. labeled ign 1. 

Start easy. 

1. Replace the fuse. Dont care if it is blown or not. Check and report condition of pins.

2. If there is any corrosion that box needs to be pulled and closely inspected.

3. Disconnect battery. Pull fuse, ohm the pink wire from the fuse to the pcm plug pin 19. 

Report 

4. For a good reference touch the 2 leads together on the multimeter and that number would be your 0. 

If you are not comfortable with this then you need to have someone experienced do this

OK, so I've been sick the last few days, but trying to do a little. I don't have any new fuses. I took out the fuse in IGN 1 and tested it with a multimeter . It tested good. Looks clean and don't really see any bad corrosion. Took a pic, will try and add here. I also took the fuses out of a few others and checked them. All checked good. I cleaned it up a little with electronic cleaner and put fuses back in different locations. 

OK, to ohm the pink wire to pcm plug pic 19, you're talking the plug to the PCM? I'll have to pull that all apart again. I feel like crap right now so I'll give that another day or so. Basically that's done the same way I tested the fuses? 

20181017_153042 SMALL.jpg

Edited by jndnaps

CaddySig_zps68ef241b.jpg

Share this post


Link to post
Share on other sites
On 10/16/2018 at 1:04 PM, BodybyFisher said:

Analysis:

Ignition 1 and Ignition Supplement are powered any time the key is in the CRANK, RUN or ACC positions. Ignition 0 is powered in ALL key positions except LOCK and CRANK

So, Ignition 0 and Ignition 1, are powered when the key is in RUN, that is when the test is run to determine that the voltage is within 2 volts OR....P1634 is set.

Tasks > 1) determine where Ignition 0 and Ignition 1 obtain their voltage (they get it from 2 different fuses), 2) test the voltage on Ignition 0 (terminal 18) verses the voltage on Ignition 1 (terminal 19).   Obviously without testing for voltage we know that it is different because the P1634 is set. 

>>>>>>>>>Test the voltage at the fuses at IGN 0 (ENG) and PCM (IGN) and report back <<<<<<<<   Once you tell us the voltages we will know more.   (my guess is.... that you will find the same voltage at the fuses, but lets see)

I have read elsewhere that P1634 is like a 'safe mode' of the PCM  

Rock's advice of replacing the fuse is good but test voltages at the fuses first.   You can use your volt meter when the engine is running to test the voltage (put the voltmeter on the lowest scale that covers 12 volts) by touching the contact points on the fuse.   Report back what you find in voltage when the engine is running..

I would do these tests BEFORE messing with intake gaskets and cracked or leaking intakes, P codes MUST be eliminated first.

 

P16340001.jpg

OK, on the meter I have I would put it on 20? That's what I put it on when I test the battery. Also, with the car running? and the black connected to the NEG of battery? Bare with me, I'm kinda getting confused with the multiple replies and me being sick.  
 

On 10/16/2018 at 1:20 PM, BodybyFisher said:

if you look at the top of this fuse, you can see that there are test points to test for voltage, THAT is where you want to test, put your black lead on battery ground the red lead on each side of the fuse, voltage at both points should be the same.  Record the voltage on each fuse and report back here

 

iu.jpg

This is with the car running, correct? 

 

On 10/16/2018 at 4:28 PM, BodybyFisher said:

Ok, I have done some research.   There may be a misprint in the FSM, I am going to try secondary sources.  There is a confusion in CKT (circuit) 639 and CKT 539, with a possible misprint I am looking into it further

In the print below, they show CKT 639 feeding the ICM directly using a 20 amp fuse (I believe this fuse is called DISTR not PCM (IGN)) I am thinking that they have this circuit mis-labled as 639 and it should be 539.   If you look above you notice CKT 639 feeding the PCM at 2 locations (C1-37 & C2-19).  This may or may not be an issue but we need to proceed like it is an issue.  Besides testing for voltage at the 2 points I spoke about in my prior posting, test for power at the DISTR fuse, with the engine idling.

As you can see, if this circuit has problems, it feeds the ignition circuit.  I still need to find out what the wire that breaks out at S124 and connects at C2-19 on the PCM controls, I need a scan like the one below showing the PCM circuitry off C2-19.  

High resistance at S124 may be hurting the voltage supply to C2-19 driving the PCM crazy.   When you test for voltage at the PCM (IGN) fuse we will know more. 

I am going to the library to get into Alldata and see what they have

Let me know what you find.  Have patience

PCM Power0001.jpg

OK, I will try this next before I disco the plug to the pcm and try the other test that Rock mentioned. 


CaddySig_zps68ef241b.jpg

Share this post


Link to post
Share on other sites

Yes with the key in run position or engine idling.  

Personally I think it is best to TEST voltages first, that is quick easy and gives us information.

You  need to test for voltage at 3 fuses in the underhood fuse center

PCM (IGN)

IGN 0 (ENG)

DISTR


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

Yes. 

Check the voltages at the fuses first before you tear it all apart again. 

If you find that while running all the fuses show the same voltage or at least within .5 volts of each other then go farther.

To ohm the pink wire you would first pull the fuse and verify which side is the input side. It will have 12v with ignition on.

You will want to ohm from the other one to the pin at the pcm. Without fuse installed


GM FAN FOREVER

Nice, clean, luxury= fine automobile

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.