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Tim West
Tim West, ASE Certified Technician
Category: Cadillac
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Experience:  Ase certified service manager
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2002 cadillac deville: rough idle..I do have a check engine light

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I have a 2002 cadillac deville, it has developed a rough idle. At speed it is fine. I do have a check engine light. It just idles rough. What could cause this?

Read more: http://www.justanswer.com/questions/2gi21-i-have-a-2002-cadillac-deville-all-of-a-sudden-it-developed#ixzz0kERcfeoI
Submitted: 4 years ago.
Category: Cadillac
Expert:  Tim West replied 4 years ago.
Thanks for visiting Just Answer,
You said you DO have a check engine light? What codes are stored? I am guessing you have been trying to fix this problem for a while?

Customer: replied 4 years ago.
the code is for a secondary air injector
Expert:  Tim West replied 4 years ago.
Thanks, XXXXX XXXXX that is a p0418 correct? Did the engine light illuminate the same time as the the problem occurring? I am not sure if this is related to the rough idle, but I wan't to be certain.
In the meantime, let's go over why the check engine light is on.
First, Possible Causes

* AIR pump relay connector is damaged (check pins for damage, and moisture)
* AIR relay Ignition circuit is open (check the AIR PMP fuse in U/H fuse block)
* AIR pump relay control circuit is open
* AIR pump relay control circuit is shorted to ground, or shorted to voltage
* AIR pump relay has failed
* PCM has failed

Get back to me.
Customer: replied 4 years ago.
From my understanding from another one of your experts the secondary air injector is strickly for emmisions and does not have anything to do the the enging idle. What I would like to know, what I would like to know is know is what will cause the engine to idle rough it runs great as long as your pressing on the gas.
Expert:  Tim West replied 4 years ago.
Thanks, XXXXX XXXXX agree this code shouldn't cause a rough idle. However, if the engine light illuminated the same time as the rough idle, it's almost too much of a coinsedence.
Anyway, let's move on.

There is a hose going from the throttle body to the manifold. Inspect it. Also, spry some carb cleaner at the throttle body base where it mouts to the intake, check for a bad throttle body gasket. It's very common.
It wouldn't be a bad idea smoke testing the entire vehicle if possible to check for vauum leaks.
If none, try spraying some carb cleaner or wd40 into the throttle while the rough idle is present.
If the idle smoothens out with added fuel, check the fuel pressure and clean the mass air flow sensor with CRC MAF cleaner. The MAF is located on the hose coming from the air filter box.

Try disconnecting the electrical connector of the EGR valve and see if it runs better, if so replace the EGR valve.


Also there is a TSB on a camshaft issue

Subject:
4.6L LD8 , L37 and 4.0L , L47 Engine Rough Idle - kw body calibration camshaft code DTC EGR intake leak lean manifold MIL miss misfire PCM #PI01748A - (02/20/2004)

--------------------------------------------------------------------------

Condition/Concern:
Some 2000 and early built 2001 model year Cadillac Deville, Eldorado, Seville with 4.6L (LD8, L37) engines or 2001 Oldsmobile Aurora with 4.0L (L47) engine, may exhibit a condition of rough idle with no PCM DTC and no driveability complaints

Recommendation/Instructions:
The camshafts must be replaced (part numbers are listed below) on all 2000 vehicles with 4.6L (LD8) (L37) Engines and the early built 2001 vehicles (see broadcast codes listed below) with 4.0L (L47) OR 4.6L (LD8) (L37) Engines. For a 2001 vehicle, you must verify that it has the early cam profile by reading the 3 alpha characters of the broadcast code listed on the tag attached to the passengers side
of the engine's rear cam cover. The Broadcast Codes for early 2001 engines are:

Seville, Deville Applications:

ENGINE VIN CODE Y KMA

ENGINE VIN CODE 9 KKA

.

Eldorado Applications:

ENGINE VIN CODE Y KCA

ENGINE VIN CODE 9 KBA

.

Aurora Application:

ENGINE VIN CODE C KYA

.

Camshaft Service Part Numbers:

.

4.6L (LD8) VIN CODE Y AND 4.0L (L47) VIN CODE C CAMSHAFT SERVICE PART NUMBERS;

12570331 RH EXH

12570332 LH INT

12570333 RH INT

12570334 LH EXH

.

4.6 (L37) VIN CODE 9 CAMSHAFT SERVICE PART NUMBERS;

12570335 RH INT

12570336 LH INT

12570337 RH EXH

12570338 LH EXH

NOTE: the Camshaft Service Part Number information can also be found on page 7 of the July 2001 GM Tech Link Volume, No. 7

http://216.182.211.32/techlink/image...pdf/7_01_e.pdf



Once all 4 camshafts have been installed, the calibration must be updated. The dealer must contact TECHLINE and tell them that the camshafts on the vehicle have been replaced, and they will give the Dealer a VCI number to install the correct calibration. Techline must be contacted each time so that they have a record of when a camshaft change occurred on each vehicle. This will ensure that future calibration for that vehicle will be correct.

.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

Models:
(00 01 CADILLAC DEVILLE, SEVILLE, KB, ELDORADO, EB, 4.6L (LD8 , L37) ENGINE) and 01 OLDSMOBILE AURORA 4.0L (L47) ENGINE)

Tim West, ASE Certified Technician
Category: Cadillac
Satisfied Customers: 4638
Experience: Ase certified service manager
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Tim West
Tim West
Cadillac Mechanic
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Ase certified service manager