Cadillac Repair: check engine, cadillac deville, wire connector

Question
did as you instructed me to and no codes came up. the only thing that showed in the display was 4 dashes.
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Followup To

Question -
recently bought a 1986 cadillac deville fleetwood. at first the check engine would come on and then go off for awhile and then back on. now it comes on almost as soon as i start the engine and stays on. any suggestions would be greatly appreciated.

also air conditioner come on but does not cool. can you help me? thanks.

Answer -
Do this procedure:

1. Ignition switch ON. Engine OFF.

2. Simultaneously push and hold the OFF and WARMER buttons on your climate control panel until the whole display illuminates and then release the bottons.

3. You will see codes appaering and the display will stop at .7.0.

4. Turn ignition OFF.


Tell me what the codes are in the EXACT order in which they displayed.  

Answer
You should see a .7.0 after step # 2 is concluded.

The 4 dashes indicates either an ECM or BCM problem.

Here is what I want you to do. Do you know where the coolant sensor is located ?. It is located near the throttle body and has a 2 wire connector with one BLACK and one YELLOW wire attached to it and is a WHITE plug.

Disconnect the 2 wire connector and then either just turn the ignition ON and see if you get a check engine light OR start the car for NO MORE than ONE MINUTE and see if the check engine light comes ON.

If it does, Go thru the above procedure again to see if any codes display and let me know what you get.

Shut OFF the ignition and plug the coolant sensor plug back on the sensor.


Let me know.