Automobile Enthusiasts

Find the code by counting the flashes made by the "check engine light" then take that number to a parts store (I like Auto Zone or Advanced), and have them give you a read out of what is wrong. They love to do this because thy sell a lot of parts like this. Many stores will even sell you a tool like a reader, then give a full refund upon return. It's like a no fee loaner.

Meanwhile, here's a detailed method for reading the codes with out hardware. It's easier than it appears, and you have nothing at all to lose:

(Applies to all pre 1996 Ford Pick ups, not just the F-250)

The easiest way to test the computer on a 1988 Ford F-250 involves using a self-diagnostic procedure. The 1988 F-250's computer is a single unit with harness wiring and it is the heart of Ford's first generation On-Board Diagnostic (OBD) system. When accessed, the OBD-I system will flash out trouble codes via the "Check Engine" light. You'll then need to look up the active codes to determine if any relate to the Ford F-250's computer

1.
Start the engine and let your truck idle. Ensure the air conditioner remains off the entire time. Once the truck has reached its normal running temperature, shut the engine off.

2
Open the hood and locate the Self Test Outlet and Self Test Input on the F-250. Both are located at the rear of the engine compartment. The STO has a six-sided, trapezoidal shape; the STI is only one slot on a wire.

3
Connect the STO and STI by placing one end of a jumper wire into the STI and the other end into the Self Test Out slot on the STO. This slot is in a row of four slots on the hub's lower end. It is the middle-left slot.

4
Place your key in the ignition and switch to "On" without starting the engine. Count the number of times the "Check Engine" light flashes. Flashing lights is the most basic indication that the computer is functional.

5
Decipher the codes. Ford's Electronic Engine Control (EEC) codes consist of two numbers. The first number will be conveyed by the "Check Engine" light as a set of long flashes; the second number will represented by shorter flashes. For example, EEC-IV code 14 is one long flash followed by four short flashes. Write down the codes.

6
Look up the EEC-IV code for each number you jotted down. These explanations are not provided in the F-250 owner's manual. You will need to look up the codes online or by referring to a repair manual. Read through all the codes you find and look for any coding reference to "EEC," "module" or "prom."

http://www.ehow.com/read-trouble-codes/


Read more: How to Test the Computer on a 1988 Ford F250 | eHow.com http://www.ehow.com/how_7943380_test-computer-1988-ford-f250.html#ixzz1gPmaxaTF

Good luck, and don't get discouraged. You can fix this.