The check engine light came on yesterday on my 2002 Mazda Miata LS with about 140k miles on her. I checked the car using a OBD scanner, and it found 3 codes for the car: P0012- Camshaft position timing over retarded bank 1 P0301- Cylinder 1 misfire detected P0327 - Knock sensor 1 circuit low bank 1 or single sensor. After I checked the codes, (I did not erase any code) the check engine light went off . I do not notice any problem in the performance or running of the car and am generally not seeing any differences like fuel smells, leaks, or anything yet.. So I am assuming and hoping that the CEL is probably because of faulty connections or wires. Want a professional opinion about the possible problms and the approximate cost to fix

SOURCE: I had the Oil control

your timing belt has jumped 1-2 teeth i've never heard of an oil control solenoid valve

SOURCE: Check engine light comes on. p0171 and p0351 codes found

From Lusty Kid:

I know the economy is bad, but change all of the plugs. Check your PCV Valve hose, 150 rottens them out allowing air to be sucked in, thus all kinds of codes.

Depending on mileage. Dismount the EGR valve and clean passages. If you are really good dismount the throtle position sensor body and clean out passages with Choke Cleaner., dismount where the EGR valves connects to the engine, clean out passages. Also check the hose thats behind this mounting to ensure is not clogged. If clogged clean it out. If not replace it. Is about 1.5 ft. long, connects to the PCV Valve Hose.

When is the last time you change your harness. Can't remember??? Replace it. Good Luck

SOURCE: 2002 Hyundai Sonata wont pass smog

CA you can take the car to a referree and get a one time waiver if you have spent a minimum of $450 on repairs not including smog fees. Gives you two years to get it fixed. Smog Referee Call Center
Toll Free: 1.800.622.7733
You can also sell the car to the state for "up to" $1,000

SOURCE: Check engine light came on

THERE IS A VALVE ON THE RIGHT SIDE OF THE INTAKE MANIFOLD THAT OPEN THE RUNNER.IT HAS A VACUUM LINE TO IT.FOR IT TO BE STUCK OPEN EITHER THE SOLENOID IS BAD,THE VACUUM LINE IS BAD OR THE RUNNER IS GUMMED UP WITH CARBON AND STUCK OPEN

SOURCE: Check engine light and air conditioning

I Think I Can,
You Might Be Blending Hot Air With A/C Cold Air And Being 100Deg Outside, Your Getting
Really Warm/Hot Air Inside,
Your System Is Charged w/Freon, The A/C Compressor Is On/Engaged,
There Are 2-Aluminum Tubes Comming From The Compressor, [In & Out Pressure]
1 Tube Will Goto The Front Condensor, Infront Of The Raidator,
The OTHER Tube Comming Out Of The Condensor Will Goto A Dryer,
[Aluminum Looking Cylinder] Bigger Aluminum Tube[s]
The DRYER Will Then Feed Freon To Your Evap-Coil Inside Your Car [Cool-Air],

OK, The Dryer Tube's, 1 Of Them Should Be Cool/Cold, Locate That Tube, A Thermometer
wrapped w/Alum-Foil Around This Tube,
A/C ON, [A/C Compressor Engaged]
If You See The Temp Is Around 50-55 Degree's Or Lower, You Have Cold Air,
If Not, Above That, Low Freon, Or A restriction In The System. [Comes Later]
You Have Cold Air, You Have Warm/Hot Air Inside Car/Vents?
You Are Blending Hot Air w/Cold A/C Air, Problem Is With Heater-A/C Blend Box
Under Dash. There Are 2 Seperate Coils Under The Dash,
1 For Winter/Heat, Other [Evaporator Coil] For A/C, There Is a Diverter/Flapper door
That, For A/C, Closes Off The Heater Coil, Or It Should, To Prevent Engine Hot Water/Heat
From Blending w/ Cold A/C Air.
Most Are Controlled By A Diaphram, Vaccum Controlled From The Heater-A/C Controller
On The Dash.
If You Can Select From Defrost Vent To Dash and Floor Vents, Most Likely you Have
a Bad Diaphram That Controls The Heat-A/C Flapper Valve.
Most Time's You Can Open/Remove The Glove Box And See It,
A Temp Fix, For Cold Air, Would Be Remove The Vaccum Line From That Diaphram,
And Plug It, Pull The Metal Rod Back On The Diaphram with a Needle Nose Pliers,
If you Get Cold Air, Take a Ty-Wrap, Around The Shaft, Secure It, To Keep The
Vent In The Cold Air Position.
Then You Will Have To Get A New Diaphram Installed, Most Time's, Can Be Done
Through The Glove Box Opening.

Now About The Restriction In A System,
You Will Need A Set Of A/C Gauges, Car-Off, A/C Off, Connect Gauges.
IMPORTANT: The Gauges Before Connecting Should Show Pressure In Them [Freon]
Either The Gauges Have Freon In Them Or They Are In A Vaccum.
Otherwise They Have Air In Them, Air w/Freon=BAD Things.
OK, Gauges Show Pressure, Gauges Not Connected To Anything,
Open Up Both Knob's, Blue [Low-Side], Red [High-Side]
Gauges Needles will Move/Equal Out pressure,
BOTH Gauges Should Read Same Pressure, If Not, Quick Fix, Remove Gauge Glass
Covers, Need Little Screwdriver, If Gauges Off By ie: 4 psig,
Adjsut Low-Side [Blue] By 2psig and other, by 2psig, [Split The Difference]
So Now Both Gauges Read IDENTICAL Pressure.
Close Both Valves, Blue & Red
Connect Gauges To Car, Car=Off, A-C=Off
You Will See Pressure On Both Gauges,
Low Side Shuld Be Around 75-95psig, Depending on Outside Temp, If Around 60 or less
need freon.
OK, BOTH Gauges Should Show SAME Pressure reading,
If There Is MORE Than a 4psig Difference Between Them,
There Is A restriction In The System,
a Plugged "Orfice Tube" [Filter] Part Cost $3.00, Servicing The Filter, Alot More.
Restriction Causing Might Be , Moisture/Air in System [Improper Vaccum On System During Last Repairs], Compressor Breaking Down [Metal, Black Goo Bul-up]

Hope You Get Some Cold Air Soon.