A cheap and quick way to see if your truck is going into closed loop 88-94

[Yeti_Owner]

Jump the OBD connector between A&B ports (the same as when you pull codes). Start the truck. The check engine light will flash rapidly. Start driving, once it warms up, the 02 lights off, and when switches into closed loop operation, it will change to a slow flash.

If it does this, you can have a reasonable assurance that things are "ok" with your ECU and engine management system. This isn't a cure-all for diagnosis, but just a simple rough check.

If it stays rapid once warmed up, you have issues, and need a scantool to see which sensor is acting up.

Quick-tip

 

[Yeti_Owner]

And....for no reason at all, except it made me laugh:

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[heavyjunk]

And....for no reason at all, except it made me laugh:

You must be registered for see images attach

priceless