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03 CTS 3.2L Engine Idles Rough


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Hello i have a 03 cts that according to the local cadillac shop who i paid nearly $100 to tell me this car has a history of misfires.

The car runs perfect except when youre sitting at a stoplight it idles a little rough.

When you first start the car when its cold it idles faster and its smooth.....turn the heat on and the engine slows and there the "miss"

All you have to do is just barelt touch the accelerator and the vibration/miss goes away.................

This is driving me nuts.

They suggested changing the spark plugs which i did and that didnt help any.....no change.

Any ideas?

No computer errors!

kentucky

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Get the OBD II trouble codes and post them here. Here's how to get the codes:

http://www.caddyinfo.com/readingcodes.html

Reading the codes is probably all your $100 got you. Let's see if there is anything else. Others with experience with your engine will chime in after you post the codes.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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They didnt say there were any codes on the miss......i think the history was from the car history over the years for service work,,,,,,,

Ill do what you said though as i have no idea here.

kentucky

Get the OBD II trouble codes and post them here. Here's how to get the codes:

<a href="http://www.caddyinfo.com/readingcodes.html" target="_blank">http://www.caddyinfo.com/readingcodes.html</a>

Reading the codes is probably all your $100 got you. Let's see if there is anything else. Others with experience with your engine will chime in after you post the codes.

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Thanks for the link but i read all of it and there are no instructions there on getting the codes from a 03 cts....

these dont work:

DTC display; 1998-2004 Seville and 2000-2005 Deville

by JimD

Use the 3 switches located to the right of the Driver Information Center (DIC) to activate and respond to the OBD prompts on the DIC.

ON/OFF = YES

INFO RESET = NO

INFO DOWN or INFO UP = manual toggle

Ignition ON, acknowledge any warning messages; press ON/OFF and INFO UP together for 2 to 3 seconds. Everything in front of you lights up for 4 or 5 seconds, then you will see

the cts doesnt have the on/off anywhere i can find!

help?????

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For the 2003 CTS Non-Nav, turn on the ignition without starting the car. Push in the F1 and the F6 function keys on the radio at the same time.

For the 2003 CTS with Nav, Press the BAND button and the bottom NAV button to the left of the display, then release.

Does not work on 2004+ models, which require a code reader.

Notes added to the Reading Codes page.

Bruce

2023 Cadillac CT4-V Blackwing

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Thanks...that got me started.

I got this screen

OBSD

Clear all Codes...(highlighted)

AMP 09354906 20C0

CCP 25743625 3220

Then theres a small arrow pointed down on the right side........ i guess this means there are more codes?????................

I couldnt find anything that would scroll up or down or select?????????????????????

thanks

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Ok figured it out..........

Which codes do you want as there are about 60......

the most popular one seems to be U1301H

But ill post them all if you want them or just tell me which ones you need.

DDS...Dim...IPC...IRC...LRD....AMP???????????

A friend read it today with his scanner and he said it looked like to him a throttle position sensor might be bad......

checked at the local caddy parts store they dont sell it like that you have to buy the whole unit....wholesale 267.00

I would like to be really sure b4 i buy this...............

thanks

kentucky

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U1301 High voltage on the class 2 serial data circuit.

B1004 Keep alive memory

B1372 DIM has detected low voltage on IGN 1 with engine running, accessory voltage high

B1382 DIM has detected low voltage on IGN 1 with engine running accessory voltage low

Uxxxx lost communications with xxxx

DTC U1000 and U1255 Class 2 Communication Malfunction

DTC U1001-U1254 Lost Communications With XXX

DTC U1300, U1301 or U1305 Class 2 Data Link Shorted

DTC U1713 or U1715 Loss of Front Door Module to Window Motor High Speed Comm.

DTC U1714 or U1716 Loss of Front Door Module to Window Motor Normal Speed Comm.

DTC U1800, U2104, or U2106 Controller Area Network (CAN) Bus Communication

DTC U2100 Controller Area Network (CAN) Bus Communication

DTC U2102 More Controllers On Bus Than Programmed

DTC U2105 Lost Communications With Engine Control System

DTC U2153 VICS ECU Communication Error

Complete listing of DTCs for the 2003 CTS added here: http://www.caddyinfo.com/dtc_2003cts.htm

Bruce

2023 Cadillac CT4-V Blackwing

Follow me on: Twitter Instagram Youtube

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Thanks

im guessing all these are old codes and i should erase them and see what comes back?

or

did you see something that would make it idle rough?

U1301 High voltage on the class 2 serial data circuit.

B1004 Keep alive memory

B1372 DIM has detected low voltage on IGN 1 with engine running, accessory voltage high

B1382 DIM has detected low voltage on IGN 1 with engine running accessory voltage low

Uxxxx lost communications with xxxx

DTC U1000 and U1255 Class 2 Communication Malfunction

DTC U1001-U1254 Lost Communications With XXX

DTC U1300, U1301 or U1305 Class 2 Data Link Shorted

DTC U1713 or U1715 Loss of Front Door Module to Window Motor High Speed Comm.

DTC U1714 or U1716 Loss of Front Door Module to Window Motor Normal Speed Comm.

DTC U1800, U2104, or U2106 Controller Area Network (CAN) Bus Communication

DTC U2100 Controller Area Network (CAN) Bus Communication

DTC U2102 More Controllers On Bus Than Programmed

DTC U2105 Lost Communications With Engine Control System

DTC U2153 VICS ECU Communication Error

Complete listing of DTCs for the 2003 CTS added here: http://www.caddyinfo.com/dtc_2003cts.htm

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There are so many network codes, most with the voltage stuck high (shorted to 5 Volts or 12 Volts) that I would imagine that you have a network problem. I don't have information on the CTS but on my car the network is on the purple wire.

Since you have so many codes, I would clear them and see what comes back, as you ask. I would fix the network problem or whatever comes back quickly. A network problem can interfere with the PCM operating the engine properly and thus fixing the network problem may fix your rough idle.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I did have b2470c

b3832c

p2107c

ending with c does it mean current?

Ill erase them all and post what comes back...

i see the p2107c is:

DTC P2107

Throttle Actuator Control (TAC) Module Internal Circuit

I think this is what i was told was bad...would it make the car idle rough????????

thanks

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Yes, "H" = History and "C" = Current.

I don't know if a TAC could cause a "rough" idle. I would expect it to cause an high or low idle, but that is just me applying some logic.

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B2470 Cellular Phone Antenna Circuit Fault

B3832 Window Position Sensor Circuit

P2107 Throttle Actuator Control (TAC) Module Internal Circuit

Look for a connector or wiring problem with the TAC.

Also, when the other codes start coming back, go after electrical problems that they point to. You have too many codes for there not to be an electrical problem, probably with the network.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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A friend told me to clean the throttle plate he called it.

Wow......did that make a difference.

No rough slow idle now.

Was idle around 500 to 600 rpm now 800 to 1100 rpm....no miss.

The only codes that came back were

B3832c and it will not let you erase it!

B2470c

B2365H...i know h means history but i erased them all b4 going to town.

Now the only noticeable issue is something different...now the car rpm varies...while sitting still it will go from 750-800 rpm to 1000-1100 rpm and then back.

If you turn the cars heater off the fluctuation is still there but not nearly as much...maybe 850rpm to 950rpm.....

I really appreciate you guys helping me......maybe i can help someone down the road..

kentucky

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First you have to locate it. The fix will depend on what it is. Spray some Brakleen around the manifold base, TB to manifold mount and anywhere else that the might suck in unmetered air including vacuum hoses. If the RPM rises, you found a leak. Fix whatever it is, tighten down manifold or replace the gasket, replace cracked vacuum line or plug it back in if hanging loose etc.

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