Here are a couple diagrams for retrieving codes...
Auto Repair Manual - How to read codes (No Special Tools Needed)
1 Ensure the engine and oxygen sensor is up to operating temperature.
2 Turn the ignition OFF.
3 Connect an LED tester or Voltmeter, (Click here for details) to points labelled A and B on the diagram
4 Use a wire link to connect terminals as shown on the diagram.
5 Start Engine.
6 The fault codes will be shown on the LED tester or Voltmeter connected.
7 Read codes as described in the Code Format Description below.
8 Press the continue button to enter the code numbers and get the code description.
Ford KOER diagram above is described as follows
" Engine Running ID Code. Number of reflects cylinders in vehicle. (diagram shows a 6 cylinder vehicle)
2 = 4 Cylinders
3 = 6 Cylinders
4 = 8 Cylinders
5 = 7.3L Diesel
" If the vehicle is equipped with a Brake On/Off (BOO) switch, the brake pedal must be depressed and released after the ID Code is transmitted.
" If the vehicle is equipped with a Power Steering Pressure Switch (PSPS), the steering wheel must be turned atleast 1/2 turn and released within 2 seconds after the engine ID Code is transmitted.
" If the vehicle is equipped with the E4OD transmission, the Overdrive Cancel Switch (OCS) must be sycled after the engine ID Code is transmitted.
" A 6-20 second pause.
" A single flash indicates the Dynamic Test Responce Code. When observed briefly take the engine to wide open throttle.
" A 4-15 second pause. during this time ignore any quick flashs that may occur.
" Fault code 132. (vehicle will either emmitt 2 or 3 digit codes)
" A 4 second pause seperates next Hard Fault Code.