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
Engine-Codes OBDII Code List
P1512 Mazda - Variable Tumble Control Solenoid Stuck Closed
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- 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
- Engine Light ON (or Service Engine Soon Warning Light)
Read more: http://engine-codes.com/p1512_mazda.html#ixzz3ihjeps00