How to Troubleshoot a 1990 Toyota 22Re with the Engine Light On

Modern engines have microprocessors everywhere

Modern car engines use microprocessors to control many systems. Though they run cleaner and more efficiently, troubleshooting these engines requires accessing an onboard diagnostic (OBD) computer. When the OBD senses a fault, it stores a diagnostic code and turns on the trouble light, or "check-engine" light. For post-1995 vehicles, OBD codes can be read with a handheld OBD-II code reader. If the vehicle is older than 1995, mechanics can read an OBD-I code by decoding a series of blinks controlled by the OBD. This code can then be cross-referenced with a chart of codes to determine where the fault detected by the OBD lies.

Difficulty:

Moderately Easy

Instructions

things you'll need:

• Wire for a jumper
• Ignition key
• OBD diagnostic code chart (under "check engine" in owner's manual)

1. • 1

     Turn the vehicle's ignition switch off.

   • 2

     Open the hood and locate the connector box. This is a small box, near the main fuse, marked "Diagnostic."

   • 3
     Connect the terminals with a short length of wire repair of an old radio receiver 1. image by wrangler from Fotolia.com

     Open the box and connect terminals E1 and TE1 with a jumper wire. Be careful not to connect other terminals.

   • 4

     Turn on the ignition, but don't start the engine or press the accelerator.

   • 5

     Watch the check-engine light, which will begin blinking. A regular on-off pattern (both on and off are about one-quarter second long) means that no trouble code has been stored. Other patterns contain a code in two sets of blinks a half-second long and separated by a half-second. The sets are separated by a one and a half-second pause.

   • 6

     Count the blinks in the first set, then count the blinks in the second set. A pattern of three blinks, pause, one blink means code 31. A pattern of one blink, pause, four blinks, means code 14, and so on.

   • 7

     Record the blink code, and check it against the cross-reference chart in the owner's manual to determine the meaning of the code.

Tips & Warnings

• Many sites on the internet list OBD-I codes if you don't have access to the owner's manual. Check multiple sites against each other to verify the information..

• Using the jumper wire to short the wrong connectors can be harmful to the engine electrical system.