Check Engine Light Doesnt Come On With Key On

Radio on and full systems on.

Check engine light doesnt come on with key on.

The cap is a crucial part of a car s fuel delivery system. There is 2 key modes on the switch. A loose fuel cap is one of the most common reasons why the check engine light turns on. Here is the deal run jumper wire at diagnostic connection but instead of first 2 slots go with 1 and 4 if check engine light comes on its the circuit board in module under dash its about 2 inches wide 4 inches long either lite green or gray or black plastic tube box with a door on one end will be tape up alongside wiring cut tape open lid and there is a small circuit board that handles lie and codes from computer.

If the check engine light doesn t come on in the run position it means the computer failed the self test mode and there s a problem with the computer. When turning the ignition switch to the run position the check engine light should come on. It then goes to the electronic control module. So if you go to the ecm and check for voltage on pin a5 then you can eliminate everything except the ecm.

Do not check resistances. This way you can sit and listen to the radio without everything else draining. It notably prevents gasoline fumes from leaving. Radio on mode only allows you to use the radio.

The light bulb for cel has a power feed with 12 volts runing to it with key on all the times. Since you said the other lights work then. This is called the self test mode for the computer. Ok it looks like fuse 7 in the dash fuse box supplies power to the check engine warning light.