1997 Dodge Dakota Failed Smog Test

My 1997 Dodge Dakota failed the smog check for high emissions and OBD NOT READY.

At 15 MPH HC(PPM) test FAILED: Max 49, my Dakota Measured 75 ppm. At 15 MPH NO(PPM) test FAILED: Max 501, my Dakota Measured 681 ppm.

I always use Chevron gas & put 91 octane gas and added 4 oz. "MARVEL gas/oil additive" into gas tank same day of test. Could this cause these 2 FAILS (above)?

Also, OBD system check FAILED. Few days before the smog test, I disconnected battery cables to clean battery. Could this cause this FAIL?

Answer:

Your Dodge Dakota's OBD II failure is most likely due to having the battery disconnected a few days before the smog test. This cleared the engine control module's "readiness flags" which when READY or COMPLETE, indicate the emissions system is functioning properly. Driving your truck for 200-300 miles and over the course of a few days (in both highway and city driving conditions) will allow the readiness flags to become ready once again.

The high emissions faults need to be diagnosed by a smog check repair station. It is unlikely that using 91 octane fuel and/or the Marvel fuel additive caused your Dakota's high HC and NOx faults. 91 octane fuel normally would have reduced NOx emissions; so probably not at fault. More then likely there's an emission component related fault which is increasing NO and HC in this case. A hands-on diagnosis will be required.

posted by SmogTips Support