Check engine light is on

CRAIGP1148

MEMBER
2003 TOYOTA COROLLA
1.6L
4 CYL
2WD
AUTOMATIC
200,000 MILES

I connected a obd2 to the car the wifi connects but it will not communicate with the car. It keeps telling me it cannot communicate with the car so I cannot get rid of the engine light. I have tried three different obd2 connectors same problem with all of them.

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
43,070 POSTS

Hello,

There is a fuse ODB 7.5 amp that needs to be checked and if okay please check the ground at the ALDL connector. Here is a guide to help check for power and ground with the wiring diagrams for he connector so you can see how it works and the fuse location as well:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

Cheers, Ken

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Monday, November 12th, 2018 AT 11:10 AM

CRAIGP1148

MEMBER
4 POSTS

I have checked the fuse that is okay, obd2 powers up and when it says linking to car it does not link. When I turn the key of it says turn key on to connect but it will not link to car.

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Thursday, November 15th, 2018 AT 6:47 PM

KEN L

MASTER CERTIFIED MECHANIC
43,070 POSTS

Does the car run? Here are other fuses you should check for power in the PCM diagrams. I would check the grounds as well. It sounds like the computer might be bad. Check the EFI relay as well.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

and

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what happens.

Cheers, Ken

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Friday, November 16th, 2018 AT 1:00 PM

CRAIGP1148

MEMBER
4 POSTS

Hi Ken, the car starts fine if I have tried everything but still will not connect to the obd11. If I pull the battery lead of when I start the car the engine light goes off, but when I switch it off again and start switch the engine light stays on.

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Sunday, November 18th, 2018 AT 5:15 AM

KEN L

MASTER CERTIFIED MECHANIC
43,070 POSTS

If the wiring is okay and the scanner is working then the only thing it leaves is a bad PCM. I would try a used/rebuilt one and plug it to see what happens. Here is the location.

Please let us know what happens.

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