I've seen this posted in a few blogs but I figured I'd post up here on WF for anyone who didn't know this trick.
1. Insert your key into the ignition and turn it to the "ON" position but DO NOT start the engine.
2. While keeping the key pushed into the ignition cylinder, turn it to the "OFF" position and then back to the "ON" position.
3. Repeat Step 2 two more times and make sure it ends in the "ON" position.
NOTE: Make sure you are pushing it in so it doesn't catch at the other positions.
If you do it right, your dash will light up like a Christmas tree and your odometer will show all dashes. If you have any stored codes, it will cycle through them after the dashes. If you don't have any, it will show "-done-".
After that.. do a search for the codes to diagnose the issues.
Codes are a letter followed by four numbers:
The first letter dentes the code is related to
B - Body
C - Chasis
P - Power Train
U - Network
The second is to determine whether it is SAE or MFG.
0 - SAE (standardized code)
1 - MFG (manufacturer specific code)
Third number is for:
1 - Fuel & Air Metering
2 - Fuel & Air Metering (Injector Circuit)
3 - Injection Systems or Misfire
4 - Auxillary Emissions Control
5 - Vehicle Speed Control & Idle Control System
6 - Computer Output Circuit
7/8 - Transmission
The last two are for the specific fault (00-99)