How to reset check engine light?

I have heard about the cranck sensor coukd be the problem

the following link is courtesy of obd codes .com the p0300 misfire code can be from the other to codes P0051 - Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 2 Sensor 1) OBD-II Trouble Code Technical Description Generic: Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 2 Sensor 1) Nissan: Heated oxygen sensor (HO2S) 1 Bank 2 - heater voltage low What does that mean? A P0051 DTC (diagnostic trouble code) refers to the O2 sensor (oxygen sensor) located on Bank 2 in front of the catalytic converter. There is also an oxygen sensor behind the converter which is Sensor #2. This O2 sensor #1 may also be refered to as an air/fuel ratio sensor since on some vehicles it is. It detects the amount of oxygen in the exhaust gas compared to the outside air and then vehicle's computer adjusts the air/fuel ratio going into the engine. The sensor is less effective when the exhaust gas temperature is low, so it includes a heater which is activated to help get better readings from the A/F O2 sensor. Essentially this P0051 code means that the resistance of the heater circuit is lower than normal. In most cases, that resistance level must fall below 0.8 A to trigger the DTC code. Note, this code is very similar in nature to P0031, P0032, and P0052 Potential Symptoms Most likely you'll not notice any symptoms other than the MIL (malfunction indicator lamp, a.k.a. the check engine light) will illuminate. Causes A P0051 DTC trouble code may be caused by one or more of the following: A short in the heater circuit in the sensor A failed O2 sensor heater Wiring/connectors broken/frayed leading to sensor and/or relay Failed PCM/ECM Possible Solutions To fix a P0051 DTC code, you'll need to do a proper diagnosis. To do that, you'll want to inspect the wiring and connectors leading to the sensor. Also if equipped with a heater relay and fuse, you'll want to check those as well. Use a digital volt ohm meter to: check for 12 volts at the heater circuit feed (hint: unplug the sensor and check at the wiring connector to do this measurement) check the ground circuit for continuity measure the resistance of the heater circuit (done on the sensor itself) measure the resistance and voltage of the wiring Refer to a service manual for the correct specifications (volts, ohms) for your vehicle. On some Toyota vehicles this code is triggered when the resistance of the heater circuit is below 0.8 A. With that said, a common fix for this DTC is to replace the air/fuel (O2 oxygen) sensor #1 on bank 2 (the side of the engine that doesn't contain cylinder #1). Please keep in mind that OEM (original equipment) replacement sensors are recommended (from the dealer). Aftermarket sensors can be less reliable and of poorer quality (not always, but more often). There's also a chance that replacement parts for the P0051 code may also fall under a federal emissions warranty (check with your dealer to see if it's covered).

Read more at: http://www.obd-codes.com/p0051
Copyright OBD-Codes.com OBD Codes Your OBD-II Trouble Codes Repair Site Home Trouble Codes FAQs Forums Store P0300 Diagnostic Code - Random Misfire Technical Description Random/Multiple Cylinder Misfire Detected What does that mean? Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly. A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why. Symptoms Symptoms may include: the engine may be harder to start the engine may stumble / stumble, and/or hesitate other symptoms may also be present Causes A code P0300 may mean that one or more of the following has happened: Faulty spark plugs or wires Faulty coil (pack) Faulty oxygen sensor(s) Faulty fuel injector(s) Burned exhaust valve Faulty catalytic converter(s) Stuck/blocked/leaking EGR valve / passages Faulty camshaft position sensor Defective computer Possible Solutions If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back. If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors. Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open. It is helpful to have access to a factory service manual and an advanced scan tool to properly diagnose a random misfire DTC. P0300 Diagnostics Video Here is a helpful video that may assist you in learning more, diagnosing, and repairing your P0300 DTC. This video is intended for auto repair professionals but could be helpful to DIYers. It shows use of an advanced OBD-II scan tool during diagnostic steps:

Read more at: http://www.obd-codes.com/p0300
Copyright OBD-Codes.com
http://www.obd-codes.com/search/?cx=006282753923640923292%3Absyyn-_1vle&cof=FORID%3A11&ie=UTF-8&q=p1512&sa=Search&siteurl=www.obd-codes.com%2F&ref=&ss=1863j1029425j5 Engine-Codes OBDII Code List P1512 Mazda
P1512 Mazda P1512 Mazda - Variable Tumble Control Solenoid Stuck Closed 0 ' Add Comment Possible causes
- Variable Tumble Control Solenoid (VTCS) vacuum solenoid stuck closed
- Faulty Variable Tumble Control Solenoid (VTCS)
- Variable Tumble Control Solenoid (VTCS) harness is open or shorted
- Variable Tumble Control Solenoid (VTCS) circuit poor electrical connection
What does this mean? When is the code detected?
Variable Tumble Control Solenoid (VTCS) Dual Plane Intake system
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)

Read more: http://engine-codes.com/p1512_mazda.html#ixzz3ihjeps00

Sound like it needs a tune up, replace spark plugs check high tension cables , make sure there is a good spark to the plugs, clean or replace air filter, replace fuel filter , check fuel pressure and flow. check fuel injectors for leaks.

Have you replaced the spark plugs or coil packs? A lot of times spark plugs will only miss once a load is put on them. Here are some tips to help you narrow it down. All you need is a screw driver and a code reader.
First, is your check engine light on?

----> if yes, try to get the code it is throwing

is the code current?

----> if no
1. Pop the hood
2. Remove the air filter box cover and inspect the filter
---> is the air filter clean?
If no, replace the air filter
If yes, remove the engine cover -

3. Find the fuel rail located toward the back of the engine bay and find all 4 injectors.
Place your thumb over the end of a long flat blade screw driver, place it carefully on each injector, and place your thumb on your ear. With the engine running, listen for fires from the injector
-----> are all 4 injectors firing rapidly at the same rate?
----> if yes, start with replacing all 4 spark plugs
----> if no, replace the fuel injector that is not firing

If yes ---> is the code for an engine misfire?

See above instructions

if no ----> is the code for throttle body position?

if yes ---> Replace the throttle body position sensor and perform the relearn process via tech II scan tool.

These are the most common issues with misfiring with engines, hope it helps or leads you in the right direction.

Dead Battery

• Replace spark plugs
  

• Replace rotor
  

• Check distributor cap (replace if necessary)
  

• Check timing (adjust if necessary)
  

• Check ignition wires (replace if necessary)
  

• Check ignition performance (firing voltage and ignition patterns)
  

• Check idle speed (adjust if necessary)
  

• Check choke (carbureted engines)
  

• Clean fuel injectors
  

• Check compression and/or power balance (identifies bad fuel injectors as well as compression problems)
  

• Check manifold intake vacuum (reveals exhaust restrictions)
  

• Check battery/charging voltage
  

• Check exhaust emissions (verifies fuel mixture, ignition performance and emissions performance)
  

• Check vehicle computer for trouble codes
  

• Install new air filter
  

• Replace fuel filter
  

• Replace PCV valve
  

• Check all emission controls (EGR valve, air pump, etc.)
  

• Check all vital fluid levels (engine oil, transmission fluid, coolant, brakes, power steering)
  

• Check belts and hoses
  

• Check safety items such as lights, wipers, tires (including inflation pressure), horn, etc.
  
  

P0301 - Cylinder 1 Misfire Detected.

Possible Causes:
- Improper spark plug at cylinder #1
- Insufficient compression at cylinder #1
- Incorrect fuel pressure
- The injector circuit is open or shorted at cylinder #1
- Fuel injector #1 may be faulty
- Intake air leak at cylinder

Possible Solutions:
- Perform Injector Service
- Replaced Spark Plug #1
- Replaced Injector #1
- Replaced Ignition Coil #1

Being you have a heavy gas smell I would look into the injectors. If injector #1 is over producing it can cause a misfire. Test your compression and fuel pressure.

P0301 - Cylinder 1 Misfire Detected.

Causes:
- Improper spark plug at cylinder #1
- Insufficient compression at cylinder #1
- Incorrect fuel pressure
- The injector circuit is open or shorted at cylinder #1
- Fuel injector #1 may be faulty
- Intake air leak

Solutions:
- Perform Injector Service
- Replaced Spark Plug #1
- Replaced Injector #1
- Replaced Ignition Coil #1

P0303 - Cylinder 3 Misfire Detected.
Follow info from P0301.

P0316 - Misfire Occurred In The First 1,000 Engine Revolutions.

Causes:
- Damaged CKP sensor.
- Ignition System.
- Fuel Injectors
- Running out of fuel
- Fuel Quality
- Base engine
- Damaged Powertrain Control Module

Solutions:
Usually the P0316 is combine with a P03XX codes. The P03XX code indicates in which cylinder the misfire occurred.

From http://www.obd-codes.com/trouble_codes/
The P0300 is a misfire and P0506 indicates low RPM at idle.

A misfire can be caused by poor ignition (spark plug, plug wire, coil, ignition module/engine control module).
OR
Poor air/fuel (air filter, fuel injector, fuel pressure, fuel filter, fuel pump, bad gas, or engine control module).

Check your maintenance requirements and see if any of these items are due for replacement first.

Check for vacuum leaks.

Air tube between air filter and intake manifold.

If the motor has over 80,000 miles then the intake manifold gasket can **** in air and leaning out the air/fuel mixture.

Give each air / vacuum relayed hose a 1/8-1/4 turn.

Get a steam cleaning on the motor and check for any sign of leak around the sensors.