Toyota Repair: how to dx check engine lite /fuel mileage, jumper wire, fuel mileage

Question
1996 previa le/sc/alltrac/ 109,000m

Hello Ted
Here is my situation I have noticed a 20%+ drop in fuel mileage in the last few weeks. Three days ago the check engine light came on. I would like to know how to dx this. I believe that there are two ports that one jumps in order to get the light to blink a pattern that can be cross referenced with Toyota trouble codes. Where is the dx block, which ports are used for this purpose and where do I find the cross reference tables?

A new twist to this situation, the check engine light has gone out....Can I still dx the problem? If not what do from here? It would still be good to know the answers to the first questions.



Thank you, Dan

Answer
This model year has the OBDII diagnostic system, there should be two DLC connectors, one is for the DTC scantool, it's located under the cover in the center of the dash where the fuses are, don't use this one unless hooking up a code reader.
There should be another connector to the left of the driver's seat, open the cover, on the inside of the cover are the terminal designations, make a jumper wire and connect teminals E1 and either T1 or TE1, it could be either but most likely will be TE1, turn the ignition to on and the check engine light should flash indicating the trouble code, this method may not give all the codes, the recommended method is to hook up a scantool(code reader).