A scan tool is preferred but you can count check engine light flashes as well. Turn the key ON, OFF, ON, OFF, ON then watch the CE light. Common codes to expect to see are 12 (one flash followed by pause followed by two flashes) that means battery has been disconnected within last 50 starts. The two digit codes are separated by a two or three second pause then the next code will come up. If you don't have AC you can expect to see 33 (open or shorted AC relay circuit). The end of sequence is code 55 (that's all folks!) At the very least you should see 55. If you don't either you didn't turn the key in the right sequence or the ECM is faulty. By all means get the scanner if you can, it will (usually) tell you the code as well as what it means, you can also monitor many engine functions/parameters while it is running. <img src="/forums/images/graemlins/cheers.gif" alt="" />