2000 Mazda Miata with OBDII read/communication error
I still have the problem of my car passing the CA required emission test, yet fails to "handshake" with smog test diagnostic computer or several code readers, besides mine. The Check Engine light was not on at first, but now it is on intermittently. This has been going on for 6 months. I have checked all fuses on the panel under the hood, and next to the ODB II plug. They have always been fine. Now what? The car does not pass emission testing if the computer wasn't working, right? Pin 16 does have 12 VDC. What do I check next? I am a laid off federal contractor and can't afford to just take it to the dealer and have them diagnose it.
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MIL is your malfunction indicator lamp, (check engine light)
CMD is the computer interface port, or OBDII port indicating a malfunction communicating with your cars computer
check all the fuses, primarily any marked pcm and retest your vehicle
note: your check engine or MIL has to be on in KOEO state (key on engine off), if the bulb is burned out everything will still work and the OBDII test computer will show MIL status ON, and if you don't have a computer to tell you that, you must get that light to light in the koeo state.
First step is to have the code or codes read.If the "check engine light" is on there will be a reason and should be a code or codes to be read.Once you have the codes,you can determine the correction needed to get that "check engine light" out and a valid emissions test completed.Get back to us with the codes found.
A failing oxygen (O2) -sensor will give failing emission tests. Normally you also get other symptoms:
- too high fuel consumtion
- bad acceleration, stalling problems, sputtering
- the check engine light comes on indicating that the engine control
unit has recorded error codes (which will be related to readings of
incorrect fuel/air ratio when read by the OBD diagnostics tool at a
It is always a good idea to see if you can get any readings from the
check engine light if present or much better by an OBD reader to be as
certain as possible.
Another component that could cause failing emissions tests is the
catalytic converter, giving a similar range of symptoms. To determine
if this is the cause is not so easy on older cars with only one O2
sensor, it requires diagnostic skills and equipment. On newer cars with
OBDII-systems it will give a recognizable fault code for the cat
Then there are also the issues of the actual cause of malfunction in
either or both of these components, is it due to old age and normal
wear and tear or is it due to contamination from burning oil (blue tail
pipe smoke) or anti-freeze (white smoke), misfiring, etc? Then the cause must be treated as well for a successful repair.
these components have a very long life span and
should not have to be replaced more than once or maybe twice for the
sensors during the car's lifetime in an otherwise health engine.
have you had the the engine codes pulled and reset?
and if so what are your engine codes?
i dont know of any car that will pass emissions test with the engine light on.
we cure your trouble that caused your engine light to come on and you will pass your test.
If it was originally intended for Texas, it's probably been made as a 49-state-compliant vehicle (CA has stricter emissions). To pass in CA, you may need some new parts for the truck in order to get it to pass. Or you may find that the best course of action is to sell the truck and buy a CA-emissions car.
The CA DMV may well have information available on how to get non-CA-compliant cars to pass the CA emissions testing.