1993 Cadillac deville 4.9. I purchased car new in 1993. 230,000 miles. Best car ever... My problem is simple I had to replace a Idle speed control motor about 4 months and used the instruction sheet that came with the parts (after market). I did not have to go through the learn idle speed process. Recently the car is somewhat unstable at idle surges it also is sailing when i let off the gas sometimes rolling along at 35 mph for a minute or two before gas fully retracts. I tried disconnecting the battery with no improvment then I found the sequence for the OBD and have a code E52. I went through the learn idle process last night with temperature at 51 degrees instructions stated be over 50 degrees. The sequence went without any issues and I could hear the idle control motor going through the adjustment process. Car seems to idle perfectly (warm condition) but too low on initial startup (cold condition). Also when I turn engine off I get clicking on the gas pedal about 10 times last 10-15 second or so. My wife thinks it cute and wanted to know if I can get her 2000 seville to do the same tune (not funny). I also get gas pedal clicking when i turn key on before starting but only 2 or 3 clicks on the pedal. Do I need to give this some time to learn the correct idle or do I have some sensor acting up. Also don't know why the cold idle is so low. Any help will be appreicated.

 

Throttle ratchet usually happens when the ISC motor adjustment screw is in contact with the throttle lever. Turn the screw in a bit and then try the ignition again till the ratchet stops. There should be a slight clearance there when the motor is warm. It will be tight only when cold and idle speed is commanded.

 

Thanks for your suggestion Cadforfun... I still am getting the throttle ratchet noise and my low idle is way too low on cold startups. I think I may have bigger problems (maybe sensors) since my cold start mode is not functioning at startup. The warm idle is about perfect and the idle learn process seems to work. I will have to either live with it or take it by the Cadillac dealership and have them check it out $$$. My E52 has rolled off and no longer displayed. I know I cause that when I disconnected the battery. I am not that familar with the code reading on the OBD built in system. I am now showing 0.70 I will either have to get a better manual that explains the code process.. OFF + WARM then HI or LOW then turn key off to exit etc. Thanks for your assistance and anyone with other suggestions are welcome to join in.

 

Finally got some time to work through my idle problem. Started to head to the Cadillac dealership but made a last resort stopped by Auto Zone. I just replaced the Idle speed control motor 4 or 5 months ago so I assumed it was not the problem. You know what assume means...***-u-me. Anyways they had no method to check other than install a new replacement under warranty to see if the problem still persist. I did the change over and installed a new idle control motor and ran through the learn idle procedure on my OBD and my low idle and thumbing gas pedal when i turn key off all disappeared. Car runs good as new. Throught I would post this to help others with idle problems...

 

@jjruggiero, thank you for taking the time to share your valuable information about your situation. I’m glad you were able to get this resolved. I’m sure members will be thankful for your post.

Michelle, Cadillac Customer Service

 

U480 OBD2 CAN BUS & Engine Code Reader

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Supported Vehicle:


Suitable for almost all cars

Product Description


Description:
With U480 code reader, you may quickly find out trouble causes (troubleshooter) of electronically controlled systems on your car, by simply connecting U480 with the 16 PIN diagnostic socket, via reading the trouble code (DTC) shown on U480, identifying, locating and checking out trouble causes with attached user's manual.
Function:
1.Works on all 1996 and newer cars & trucks that are OBD II /EOBD compliant including CAN, VPW, PWM, ISO and KWP2000 protocols

2.Reads and clears generic and manufacturer specific Diagnostic Trouble Codes (DTCs) and turns off check engine light

3.Supports multiple trouble code requests: generic codes, pending codes and manufacturer's specific codes

4.Retrieves VIN (Vehicle Identification No.) on 2002 and newer vehicles that support Mode 9

5.Highly reliable and accurate

6.Easy-to-read crystal-clear backlit 2-line LCD display

7.Easy to use with one plug-in

8.Stand-alone unit with no need for an additional laptop computer to operate

9.Small in size and conveniently fits in your palm Performs continuous DTC scan

10.Safely communicates with the on-board computer

11.No batteries needed-powered via detachable OBD II cable
Specifications:
16-pin OBDII Standard Socket

Voltage: DC 10V~12V

Temperature: -10 ~ 40

Display: 2 line LCD