So I'm reading around trying to learn more about this limp mode thing that happened to me and I'm seeing a couple of confusing threads about getting the error codes out of the ecu.

The method I've used for my 90 gxl is to ground that single connector by the battery and then turn on the ignition (not starting the car) and then read the morse code of the check engine light.

I've seen other people talk about doing this with the engine still running and imply that there are some codes that won't get stored when the car gets turned off. Is this true? Are the codes that are only available when the car is running? And if so, can I get to them without that expensive code checker widget?

-Mark

 

bump

 

No. You can read all the codes you need to right from grounding the check connector. You do not need to do it with mazda's code checker. The only other diagnostic device was a connector between the harness and ECU that took voltages for certain sensors.

-Mike

 

Is it required to have the engine off? The FSM says to do that but I just wonder if there are codes that get lost when the engine is turned off.

 

No the codes are lost when the battery is disconnected for a period of time.

Read this, it's the best walkthrough.

http://www.fc3spro.com/TECH/HOWTO/ER...KI/kerror.html