Random/Multiple Cylinder Misfire Detected
Description:
How does a P0300 code trigger the check engine light? This code will trigger the check engine light as follows:
The misfire detection monitor, a software strategy built into the computer, is designed to detect an engine misfire. The computer can also normally identify the specific cylinder in which the misfire has occurred. A misfire is nothing more than a lack of combustion, which can be caused by poor fuel quality or metering, low compression, lack of spark or unmetered air entering the engine. There are other possible, less obvious causes as well, such as uncommanded Exhaust Gas Recirculatin (EGR), flow. When the misfire monitor detects a misfire, it will trigger the check engine light with the specific cylinder number as the last digit in the P030X code. For instance cylinder 1 misfire is P0301, cylinder 2 is P0302 etc. In this case we have either multiple cylinders misfiring, or the computer simply can’t determine the specific cylinder, and as such we are left with the P0300 in computer memory.
Possible Causes:
Fuel injectors, related wiring, sensors and computer issues
Running out of gas, or poor fuel quality
Evaporative emissions system (EVAP) concerns: fuel vapors leaking into engine
Incorrect Fuel Pressure
EGR system concerns: leaking EGR valve or restricted ports
Base engine concerns: low compression, valve train problems and timing issues
Ignition system concerns including, but not limited to:
Faulty spark plugs
Faulty coil or related wiring
Ignition module or related wiring issues
Ignition related sensor faults or wiring issues
Diagnostic Help:
To diagnose a P0300 trouble code we begin by checking for proper fuel and ignition system operation, and then follow up with the less likely causes listed above, such as EGR and EVAP system problems. New style coil on plug applications have a high failure rate, and can be concluded faulty by swapping to another cylinder and checking to see if the misfire moves to that cylinder. This is a quick check if a capable scan tool or oscilloscope is not available. Always make sure the basic maintenance is done first and that things such as the fuel filter, air filter, spark plugs and spark plug wires are in good working order, as these are all possible candidates for a problem. If necessary, check for wiring and component concerns. See our article Automotive Circuit Testing 101, if you need more assistance with this. If concern is determined to be intermittent, check out our article on intermittent diagnosis and wiggle test connectors and wiring, attempting to duplicate concern. You may also use the “Get Help” link if you need specifications or have any other related questions. Remember to refer to an appropriate manual for specific instruction.
Mass Air Flow (MAF) Sensor
Description:
How does a P0100 code trigger the check engine light? This code will trigger the check engine light under the following conditions:
1. The computer receives an excessively high voltage from the MAF Sensor with the engine not running.
2. The computer receives an excessively low voltage from the MAF Sensor with the engine running.
3. The computer receives a high voltage reading from the MAF Sensor under light-load driving conditions.
Possible Causes:
MAF Sensor circuit open or shorted
Intake air leaks (unmetered air after MAF Sensor)
Defective MAF Sensor
Electronic Control Module (ECM)/Powertrian Control Module (PCM) concern
Diagnostic Help:
Monitor MAF Sensor voltage reading while increasing engine RPM. The MAF Sensor value should increase in proportion to engine speed. If not, first check for air leaks at intake tube, manifold and all vacuum lines. Then test the MAF Sensor circuits for opens and shorts. See our article Automotive Circuit Testing 101, if you need more assistance with this. If concern is determined to be intermittent, wiggle test connectors and wiring to attempt to duplicate concern. You may also use the “Get Help” link if you need specifications or have any other related questions. Remember to refer to an appropriate manual for specific instruction.
HO2S Heater Resistance (Bank 2, Sensor 3)
Description:
How does a P0061 code trigger the check engine light? This code will trigger the check engine light as follows:
The vehicle Powertrain Control Module monitors the oxygen sensor heater control circuit current draw. The check engine light will illuminate when the current requirements are too high or too low.
Possible Causes:
Possible causes for this check engine light code include:
Blown oxygen sensor fuse
Open circuit in oxygen sensor harness
Open circuit internal to oxygen sensor
Open circuit in PCM
Short circuit in oxygen sensor harness
Short circuit internal to oxygen sensor
Short circuit internal to PCM
Diagnostic Help:
To diagnose a P0061 check engine light code we will need to test out the oxygen sensor wiring and also test the circuits through the oxygen sensor itself. The internal processor circuits are a possible cause but are much less likely, so the other areas are thoroughly tested first. See our article Automotive Circuit Testing 101, if you need more assistance with this. If concern is determined to be intermittent, check out our article on Intermittent Diagnosis and wiggle test connectors and wiring, attempting to duplicate concern. You may also use the “Get Help” link if you need specifications or have any other related questions. Remember to refer to an appropriate manual for specific instruction.
HO2S Heater Resistance (Bank 2, Sensor 2)
Description:
How does a P0060 code trigger the check engine light? This code will trigger the check engine light as follows:
The vehicle Powertrain Control Module monitors the oxygen sensor heater control circuit current draw. The check engine light will illuminate when the current requirements are too high or too low.
Possible Causes:
Possible causes for this check engine light code include:
Blown oxygen sensor fuse
Open circuit in oxygen sensor harness
Open circuit internal to oxygen sensor
Open circuit in PCM
Short circuit in oxygen sensor harness
Short circuit internal to oxygen sensor
Short circuit internal to PCM
Diagnostic Help:
To diagnose a P0060 check engine light code we will need to test out the oxygen sensor wiring and also test the circuits through the oxygen sensor itself. The internal processor circuits are a possible cause but are much less likely, so the other areas are thoroughly tested first. See our article Automotive Circuit Testing 101, if you need more assistance with this. If concern is determined to be intermittent, check out our article on Intermittent Diagnosis and wiggle test connectors and wiring, attempting to duplicate concern. You may also use the “Get Help” link if you need specifications or have any other related questions. Remember to refer to an appropriate manual for specific instruction.
HO2S Heater Resistance (Bank 2, Sensor 1)
Description:
How does a P0059 code trigger the check engine light? This code will trigger the check engine light as follows:
The vehicle Powertrain Control Module monitors the oxygen sensor heater control circuit current draw. The check engine light will illuminate when the current requirements are too high or too low.
Possible Causes:
Possible causes for this check engine light code include:
Blown oxygen sensor fuse
Open circuit in oxygen sensor harness
Open circuit internal to oxygen sensor
Open circuit in PCM
Short circuit in oxygen sensor harness
Short circuit internal to oxygen sensor
Short circuit internal to PCM
Diagnostic Help:
To diagnose a P0059 check engine light code we will need to test out the oxygen sensor wiring and also test the circuits through the oxygen sensor itself. The internal processor circuits are a possible cause but are much less likely, so the other areas are thoroughly tested first. See our article Automotive Circuit Testing 101, if you need more assistance with this. If concern is determined to be intermittent, check out our article on Intermittent Diagnosis and wiggle test connectors and wiring, attempting to duplicate concern. You may also use the “Get Help” link if you need specifications or have any other related questions. Remember to refer to an appropriate manual for specific instruction.