Cruise Control tests for Ford EEC IV equipped vehicles

[Standard factory cruise control]

WARNING! FOLLOW STANDARD SAFETY PRACTICES WHEN WORKING ON A VEHICLE INCLUDING BUT NOT LIMITED TO: Transmission in Park or Neutral and the driven wheels off the ground or chocked when cranking/running the engine.
Check fan blade for cracks and do not stand next to the fan when running.
Use caution when working on fuel systems, which can remain pressurized for a long period after the key is turned off.
No smoking around fuel.
Watch for electric fan which can come on at any time.
Watch out for hot and/or moving parts.
Watch out for high voltage secondary circuits.
If you are not sure of the safety of any operation DO NOT DO IT. ASK SOMEONE!
The author assumes no responsibility for the safety of anyone using these documents.

NOTES: These tests are only available on vehicles with processor controlled cruise control systems (Taurus/Sable, some Lincoln, Crown Victoria, Grand Marquis, Thunderbird and Cougar models). These tests will not test the speed sensor. Usually there will be a regular EEC code if it is bad.

You might also want to look at the link for regular cruise above. It has a page that explains some of how the cruise works. It works pretty much the same on the processor controlled systems, but the EEC processor takes the place of the cruise amplifier.

[EEC Tester hookups]

Key On Engine Off (KOEO) test:

1. Hook a tester up to the EEC IV connector, but leave the trigger unplugged (or test switch off on some testers). Try to position the tester or light so you can see it from the driver's seat.

2. Turn key to run, and within 10 seconds press the cruise control ON button.

3. One pulse should be output to indicate the test is in progress.

4. Press in sequence: cruise control OFF, COAST, ACCEL, and RESUME buttons. Tap the brake pedal once to light the brake lamps.

5. Codes will be output (11 is a pass).

Key On Engine Running (KOER) test:

Make sure the vehicle is safe to run (see precautions at the beginning of this document).

1. Hook up per KOEO test above.

2. Start engine and within 30 seconds, press the cruise control ON button.

3. Within 15 seconds, hook up the test trigger (or move the switch on some testers).

4. One pulse should be output indicating the test is in progress.

5. Code(s) will be output after test is finished (11 is a pass).


Key On Engine Off (KOEO) codes
23 - See regular EEC code 23
47 - Switch(es) inoperative
48 - Switch(es) stuck On
49 - Switch ground open
53 - See regular EEC code 53
63 - See regular EEC code 63
67 - See regular EEC code 67
74 - No brake On\Off cycling (possible short to ground)
75 - No brake On\Off cycling (possible short to power)
81 - Servo Vent solenoid circuit problem
83 - Servo Vacuum solenoid circuit problem

Key On Engine Running (KOER) codes 27 - Servo vacuum bleeding down
28 - Servo vacuum bleeding down (possible dump valve problem)
36 - Cannot increase engine speed (possible vacuum or cable problem)
37 - Cannot decrease engine speed (possible throttle cable binding problem)

Speed sensor:

If the cruise control passes the self tests but still does not work, check the speed sensor and circuit, or substitute a new one.

Copyright 1997-2005 Dali Design

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