Consistent Check Engine light
 

I am a new owner of a 1993 RX7 with only 13k miles. I have only put about 500 miles on it since I bought it last summer and it drives GREAT. Unfortunately, every time I drive it, the Check Engine light illuminates about 15 minutes after starting and does not turn off. Performance does not seem to be affected by the CEL but it obviously is not a good thing to have happen. I brought it into a Mazda dealer and they are advising that the ECU is bad as "it is not effectively communicating with the O2 sensor thus making the engine run too rich or too lean, hence the CEL". Since I am new to these cars, I was hoping you guys could chime in on if this is a likely scenario as they are quoting ~$900 for the new ECU. Any opinions would be appreciated.






Greg in AZ

Congratulations on the car Greg. Sounds like a nice one.
Are you at all experienced when it comes to maintenance and minor repairs on cars? I'm not bashing you, I'm asking because there is a way to pull the diagnostic code causing that CEL (presumably the O2 sensor) but it's no use if you're not comfortable in fixing the issue yourself. If not, I recommend a trusted repair shop. Preferably a shop that's familiar with the car, but if it is an Oxygen sensor, it is nothing that requires special tools or experience with a rotary. And I have serious doubt that you're in need of an ECU.

The error codes were 15 & 17. I personally am not mechanically inclined this the trip to the dealership. Today I ran into another FD owner and he is giving me his shop's info in case the dealer is jerking me around on this.

welcome to the board. :)

i am inclined to believe that the dealer is feeding you a load of crap! they're probably trying to get you to replace the ECU before they tell you the O2 sensor's dead.

Not a technician, but IIRC, code 15 essentially means the O2 sensor isn't producing enough voltage to the ECU. And code 17 means the ECU isn't seeing any voltage. So if the O2 sensor has completely failed...or the wiring back to the connector is broken, it could be responsible for BOTH codes. Changing the O2 sensor and it's wiring pig-tail back to the connector is relatively easy and inexpensive... and appropriately it would be the first thing to be done to see if it clears BOTH codes. So if the O2 sensor wasn't replaced by the dealership and they're claiming the ECU needs to be changed, they are WAY premature. IF that's the case I'm with styx...they're feeding you a load of crap.

https://cimg7.ibsrv.net/gimg/www.rx7...3cbe6a2670.jpg

Thanks for the feedback...I will replace the O2 sensor and get back to you guys!!!

relevant link: https://www.rx7club.com/3rd-generati...-codes-851414/

your car is quite a looker. :)

Freudian slip? if so, i feel your pain. Styx has scarred me, too. everytime i'm with a toothless prostitute, i find myself asking "who's Styx is this?" [boo-boom pssh!] :blush:

Yeah, sorry for the mistaken credit. He beats me to a lot of the threads...force of habit. I think we agree, a dealership is rarely a place to take one of our cars.

And I think we also agree that we don't like people like misterstyx69 down here in the States. We're a little more discriminating when it comes to the north border. I pulled some professional strings and am circulating a copy of his passport photo just in case....:)

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