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New exhaust... now getting codes :/


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Hello all... I have a 2002 Cadillac DTS with 96,000 miles... The car runs great, idles good, and hasnt given me any problems yet. I changed the oil last week and this week decided to put a custom exhaust on... I still have the catalytic converter, but I deleted the resonator and ran 3 inch pipe from the cat to a 2 1/2 inch Y-Pipe with Summit Race Mufflers... The car sounds great now. The shop who I deal with has done exhaust work on my 2009 Nissan and 1987 Caprice with no issues. When I got home, I noticed the "Service Engine Soon" light was on... I read the sticky on here and read the codes for the computer and this is what I came up with... So far, the car starts good, idles good, and drives good... These are the codes I have...

PCM P1860- Current- TCC PWM Solenoid Circut Electrical

AMP U1064- History- Loss of Communication DIM

IPC U1000- Current- Class 2 Communication Malfunction

Are any of these codes serious? What can I do to correct them? Are they related to the exhaust work? I was thinking about disconnecting the battery for 30 seconds and clear the codes and see what happens... The TCC I'm assuming is the Torque Converter Lockup... Any help would be appreciated. Thanks! I already cleared the codes once and these are the ones coming back... I hope the PCM or TCC isnt damaged... What do you guys think?

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This one PCM P1860- Current- TCC PWM Solenoid Circut Electrical seems interesting. The other two not really issues.

If p1860 was temporary it will self-clear on 3rd restart without issue.

See discussion http://caddyinfo.ipbhost.com/index.php?showtopic=26672&view=findpost&p=160906

also http://caddyinfo.ipbhost.com/index.php?showtopic=7683&view=findpost&p=64870

and diagnostic chart http://drupal.caddyinfo.com/?q=node/109

Circuit Description

Ignition voltage is provided to the torque converter clutch pulse width modulation (TCC PWM) solenoid valve . The PCM controls the ON and OFF time of the solenoid by providing a ground through the output driver module (ODM) . The PCM uses a PWM duty cycle, in order to control application and release of the TCC. When the solenoid is commanded OFF, the PCM senses high volts. When the solenoid is commanded ON, the PCM senses low volts.

If the PCM detects a continuous open, short to ground or short to voltage in the TCC PWM solenoid valve circuit, then DTC P1860 sets. DTC P1860 is a type B DTC.

Conditions for Running the DTC

The system voltage is 8-18 volts.

The engine run time is greater than 5 seconds.

The engine is not in fuel cut off.

The TCC PWM solenoid valve duty cycle is 10% or less or 90% or greater.

Conditions for Setting the DTC

The TCC PWM solenoid valve feedback circuit indicates a continuous open, short to ground or short to voltage for 4.3 seconds.

Action Taken When the DTC Sets

The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.

The PCM inhibits TCC engagement.

The PCM inhibits 4th gear when the transmission is in hot mode.

The PCM freezes transmission adapt functions.

The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.

The PCM stores DTC P1860 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.

A scan tool can clear the MIL/DTC.

The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.

The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM.

P1860.gif

Bruce

2016 Cadillac ATS-V gray/black

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Thanks for the quick reply... When I cleared the codes, I left for work and the light didnt come on, but when I left work, on the way home, the light came back on... The motor is turning around 2100-2200rpms at 60mph... Is this normal for the Northstar? Is it possible that the TCC was fried during the welding of the exhaust? Thanks! I will let you know if it self clears tomorrow night... I started the car last night and the light came on on the way home... I will start the car again at 4pm to go to work and then start it again at 12am to go home from work, so hopefully it goes out.

Edited by 32VNorthstar
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Also check the transmission ponytail communication connection perhaps? Long shot, but perhaps it needs to be unplugged and replugged to 'reboot' lol.

Bruce

2016 Cadillac ATS-V gray/black

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These are unrelated to the exhaust job unless as described above the tranny plug was disturbed or or cable melted from close contact to heat caused by poor routing

It could just be coincidental however and have nothing to do with the exhaust job, I currently have this code on an 02 Chevy

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

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These are unrelated to the exhaust job unless as described above the tranny plug was disturbed or or cable melted from close contact to heat caused by poor routing

It could just be coincidental however and have nothing to do with the exhaust job, I currently have this code on an 02 Chevy

Thanks guys... Where is the tranny pigtail located? I will disconnect and reconnect when I check the rear 02 sensor.

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Your P1860 probably is coincidental, the 20 pin plug is at the front of the engine below the water pump. Disconnect the plug and meter bewteen pins U and T, you should read 10 - 15 ohms. If not the solenoid may be bad. Your RPM at 60 MPH should be 2000 with the torque converter locked up, 2200-2300 if it is not. I recently replaced the TCC solenoid on my 2003 DTS, here is a link to an overview of the video I made:

OldFart

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The plug is located at the driverside front leading edge of the tranny down and left from the dipstick and to the rear of the ABS motor

On a 96 it looks like this

ISSCrossover6_07004.jpg

Here is how to take it apart

TrannyConnector.gif

Here is the pinout discussed above by OF

4T80EConnectorEndView.gif

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

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Thanks guys... I am putting my Volant Cold Air Intake on my 2 days off work (Thursday & Friday) I will check the tranny pigtail connector and rear O2 sensor while I'm doing that replace the headlights and foglights... If I come up with nothing, I am going to take it back to the shop I got the exhaust done at on Friday and see if I can get something done to get rid of the problem... If they cant solve it, they will need to take it to the dealer and have it taken care of... I will post back my results on Thursday... What are the safe jack/ jackstand points on a 2002 Caddy DTS? Thanks!

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Thanks guys... I am putting my Volant Cold Air Intake on my 2 days off work (Thursday & Friday) I will check the tranny pigtail connector and rear O2 sensor while I'm doing that replace the headlights and foglights... If I come up with nothing, I am going to take it back to the shop I got the exhaust done at on Friday and see if I can get something done to get rid of the problem... If they cant solve it, they will need to take it to the dealer and have it taken care of... I will post back my results on Thursday... What are the safe jack/ jackstand points on a 2002 Caddy DTS? Thanks!

You seem to be implying that it's the shop's fault ("they will need to take"), I don't see that, how do you think you can 'make' them take care of it if they did not cause the problem? As noted above your P1860 is most likely coincidental, its due to a solenoid inside the tranny and NOT related to muffler work.

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

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Thanks guys... I am putting my Volant Cold Air Intake on my 2 days off work (Thursday & Friday) I will check the tranny pigtail connector and rear O2 sensor while I'm doing that replace the headlights and foglights... If I come up with nothing, I am going to take it back to the shop I got the exhaust done at on Friday and see if I can get something done to get rid of the problem... If they cant solve it, they will need to take it to the dealer and have it taken care of... I will post back my results on Thursday... What are the safe jack/ jackstand points on a 2002 Caddy DTS? Thanks!

You seem to be implying that it's the shop's fault ("they will need to take"), I don't see that, how do you think you can 'make' them take care of it if they did not cause the problem? As noted above your P1860 is most likely coincidental, its due to a solenoid inside the tranny and NOT related to muffler work.

I was told that the welding could have shorted out the sensor... unless I was told wrong... The backseat was undisturbed, so I know they didnt disconnect the battery prior to welding... Is that bogus or was I told right? If the shop didnt disconnect the battery and welded on the vehicle and caused a short that caused a malfunction... I think they should have to pay for it... Thats just my opinon...So do you think its just coincidence or could the bad sensor been caused by no disconnected battery or poor ground?

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Good muffler shops know how to weld. They know that grounding the frame and welding the muffler system can feed through the O2 sensor and to ground the muffler system itself. How can you be sure they didnt disconnect a ground anyway, what in the back seat wasn't disturbed?

I don't think its a coincidence that I have an 02 Chevy and you have an 02 Caddy with about the same mileage and with the same code and I have not had any welding done.

In addition, the TCC is a SOLENOID not a SENSOR, so it is not sensitive to any type of EMF or spikes, if one ever got there which I doubt.

Just get the TCC solenoid diagnosed and get it fixed. Check the wiring harness, connector, resistance, etc. If the resistance is not within spec, have it changed. As you noted, your muffler shop worked from the CAT back, so it would be hard to physically damage or disturb the tranny cable at the front of the engine.

Based on the discussion at the link below, it is not definate that the battery negative needs disconnecting. I also went through the service manual from 1996 through 2005 and there is NO mention of welding and having to disconnect the negative battery cable. As I said, I think its coincidence.

.

http://forums.evolut...elding-car.html

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

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I agree with BodybyFisher, it is a coincidence that your TCC failed after exhaust work was performed at the other end of the car. With the info in this thread you can troubleshoot the TCC solenoid to determine if it is defective, or is it a wiring issue on that circuit.

OldFart

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Thanks guys... I will troubleshoot and post back the results...where do I check the ohms reading at? Between plug u and t on the harness coming from the ecm to the tranny?

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Thanks guys... I will troubleshoot and post back the results...where do I check the ohms reading at? Between plug u and t on the harness coming from the ecm to the tranny?

You are testing the TCC solenoid, you are testing between the plug and the TCC in the tranny, don't test in the other direction

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

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I got a chance to check things out on my 2 days off... I checked the rear O2 sensor, that was good. I also checked the 20 pin connector to the transmission... thats good and I disconnected the battery and the SES light was still on... I took it to a shop that didnt charge to put the car on the scanner and it still came back with the 1860... Im going to do alot of asking around and see what the best quote I can get is... Im also considering doing it myself, but I am really not into FWDs...

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I got a chance to check things out on my 2 days off... I checked the rear O2 sensor, that was good. I also checked the 20 pin connector to the transmission... thats good and I disconnected the battery and the SES light was still on... I took it to a shop that didnt charge to put the car on the scanner and it still came back with the 1860... Im going to do alot of asking around and see what the best quote I can get is... Im also considering doing it myself, but I am really not into FWDs...

Hey 32v, when you checked the 20 pin connector pins U & T what reading did you get for the TCC solenoid? It should be between 10 and 15 ohms, no more no less. Anything outside of that range and the solenoid is bad and needs to be replaced. If the solenoid is within that range then more troubleshooting is in order.

OldFart

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