Is your "Check Engine Light" on? An illuminated "Malfunction Indicator Lamp" (or MIL ) means a fault has been detected in the engine control system and one or more "diagnostic trouble codes" (DTCs) are stored in the engine's computer. Depending on the nature of the fault, the lamp may come on and go off, remain on continuously or flash. Some types of intermittent faults will make the lamp come on only while the fault is occurring. When the fault goes away, the lamp goes off. Other types of problems will turn the light on, and it will remain on until the fault is diagnosed and repaired.
The Check Engine lamp has proven to be a great annoyance to many motorists (as well as professional technicians) because it seems to have a mind of its own. For one thing, it doesn't tell you anything about the nature of the problem or what the trouble code might be. It could be something serious - or it might not. There is no way to know without performing a diagnostic test on the system. Consequently, you don't know if you should stop immediately or ignore the light and keep driving. If no other warning lights are on, and the engine seems to be running normally (no unusual noises, smells, vibrations, etc.), it is probably safe to assume the problem is minor and won't hinder your ability to continue driving. But sooner or later, you should have the cause of the light investigated.
Whenever the Check Engine light comes on, a "diagnostic trouble code" (DTC) or fault code is recorded in the powertrain control module (PCM) memory. The trouble code has a number that corresponds to the type of fault. Some problems can generate more than one trouble code, and some vehicles may suffer from multiple problems that also set multiple trouble codes.
SETTING TROUBLE CODES
In most older vehicles (those made before 1996), disconnecting the computer power source or disconnecting a battery cable could erase fault codes -- at least temporarily until the trouble code resets and turns the check engine light back on. But on many newer vehicles, you do NOT want to disconnect the battery because doing so can wipe out the computer's memory settings as well as the trouble codes. This may affect the operation of the transmission, climate control system and other functions.
In most newer computer systems, fault codes are stored in a "nonvolatile" memory that is not lost if the battery is disconnected. The trouble codes remain intact until they are cleared using a scan tool
Diagnostic Trouble Code numbers are read by plugging a code reader or scan tool into the vehicle diagnostic connector (usually located under the instrument panel near the steering column). The presence of a code will turn on the Check Engine Light. The light will remain on until the code has been erased. The code number does not tell you which part has failed. It only indicates a possible fault has been detected in the circuit, system or sensor described. Further testing is usually required to isolate the fault BEFORE repairs are made. For diagnostic charts and vehicle specific repair information, refer to a service manual, or the OEM technical website
DTC CODES P0300 to P0399
P0300....Random/Multiple Cylinder Misfire Detected (Click Here for diagnostic help on P0300 random misfire codes)
P0301....Cylinder 1 Misfire Detected
P0302....Cylinder 2 Misfire Detected
P0303....Cylinder 3 Misfire Detected
P0304....Cylinder 4 Misfire Detected
P0305....Cylinder 5 Misfire Detected
P0306....Cylinder 6 Misfire Detected
P0307....Cylinder 7 Misfire Detected
P0308....Cylinder 8 Misfire Detected
P0309....Cylinder 9 Misfire Detected
P0310....Cylinder 10....Misfire Detected
P0311....Cylinder 11 Misfire Detected
P0312....Cylinder 12 Misfire Detected
P0313....Misfire Detected with Low Fuel
P0314....Single Cylinder Misfire (Cylinder not Specified)
P0320....Ignition/Distributor Engine Speed Input Circuit
P0321....Ignition/Distributor Engine Speed Input Circuit Range/Performance
P0322....Ignition/Distributor Engine Speed Input Circuit No Signal
P0323....Ignition/Distributor Engine Speed Input Circuit Intermittent
P0324....Knock Control System Error
P0325....Knock Sensor 1 Circuit (Bank 1 or Single Sensor)
P0326....Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)
P0327....Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)
P0328....Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
P0329....Knock Sensor 1 Circuit Input Intermittent (Bank 1 or Single Sensor)
P0330....Knock Sensor 2 Circuit (Bank 2)
P0331....Knock Sensor 2 Circuit Range/Performance (Bank 2)
P0332....Knock Sensor 2 Circuit Low Input (Bank 2)
P0333....Knock Sensor 2 Circuit High Input (Bank 2)
P0334....Knock Sensor 2 Circuit Input Intermittent (Bank 2)
P0335....Crankshaft Position Sensor A Circuit (Click Here for help diagnosing crank sensor faults)
P0336....Crankshaft Position Sensor A Circuit Range/Performance
P0337....Crankshaft Position Sensor A Circuit Low Input
P0338....Crankshaft Position Sensor A Circuit High Input
P0339....Crankshaft Position Sensor A Circuit Intermittent
P0340....Camshaft Position Sensor 'A' Circuit (Bank 1 or Single Sensor)
P0341 Camshaft Position Sensor 'A' Circuit Range/Performance (Bank 1 or Single Sensor)
P0342....Camshaft Position Sensor 'A' Circuit Low Input (Bank 1 or Single Sensor)
P0343....Camshaft Position Sensor 'A' Circuit High Input (Bank 1 or Single Sensor)
P0344....Camshaft Position Sensor 'A' Circuit Intermittent (Bank 1 or Single Sensor)
P0345....Camshaft Position Sensor 'A' Circuit (Bank 2)
P0346....Camshaft Position Sensor 'A' Circuit Range/Performance (Bank 2)
P0347....Camshaft Position Sensor 'A' Circuit Low Input (Bank 2)
P0348....Camshaft Position Sensor 'A' Circuit High Input (Bank 2)
P0349....Camshaft Position Sensor 'A' Circuit Intermittent (Bank 2)
P0350....Ignition Coil Primary/Secondary Circuit (Click Here for help diagnosing ignition coil faults
P0351....Ignition Coil 'A' Primary/Secondary Circuit
P0352....Ignition Coil 'B' Primary/Secondary Circuit
P0353....Ignition Coil 'C' Primary/Secondary Circuit
P0354....Ignition Coil 'D' Primary/Secondary Circuit
P0355....Ignition Coil 'F' Primary/Secondary Circuit
P0356....Ignition Coil 'F' Primary/Secondary Circuit
P0357....Ignition Coil 'G' Primary/Secondary Circuit
P0358....Ignition Coil 'H' Primary/Secondary Circuit
P0359....Ignition Coil 'I' Primary/Secondary Circuit
P0360....Ignition Coil 'J' Primary/Secondary Circuit
P0361....Ignition Coil 'K Primary/Secondary Circuit
P0362....Ignition Coil 'L' Primary/Secondary Circuit
P0365....Camshaft Position Sensor 'B' Circuit (Bank 1)
P0366....Camshaft Position Sensor 'B' Circuit Range/Performance (Bank 1)
P0367....Camshaft Position Sensor 'B' Circuit Low Input (Bank 1)
P0368....Camshaft Position Sensor 'B' Circuit High Input (Bank 1)
P0369....Camshaft Position Sensor 'B' Circuit Intermittent (Bank 1)
P0370....Timing Reference High Resolution Signal 'A'
P0371....Timing Reference High Resolution Signal 'A' Too Many Pulses
P0372....Timing Reference High Resolution Signal 'A' Too Few Pulses
P0373....Timing Reference High Resolution Signal 'A' Intermittent/Erratic Pulses
P0374....Timing Reference High Resolution Signal 'A' No Pulse
P0375....Timing Reference High Resolution Signal 'B'
P0376....Timing Reference High Resolution Signal 'B' Too Many Pulses
P0377....Timing Reference High Resolution Signal 'B' Too Few Pulses
P0378....Timing Reference High Resolution Signal 'B' Intermittent/Erratic Pulses
P0379....Timing Reference High Resolution Signal 'B' No Pulses
P0380....Glow Plug/Heater Circuit 'A'
P0381....Glow Plug/Heater Indicator Circuit
P0382....Glow Plug/Heater Circuit 'B'
P0385....Crankshaft Position Sensor 'B' Circuit (Click Here for help diagnosing crank sensor faults)
P0386....Crankshaft Position Sensor 'B' Circuit Range/Performance
P0387....Crankshaft Position Sensor 'B' Circuit Low Input
P0388....Crankshaft Position Sensor 'B' Circuit High Input
P0389....Crankshaft Position Sensor 'B' Circuit Intermittent
P0390....camshaft Position Sensor 'B' Circuit
P0391....Camshaft Position Sensor 'B' circuit Range/Performance (Bank 2)
P0392....Camshaft Position Sensor 'B' Circuit Low Input (Bank 2)
P0393....Camshaft Position Sensor 'B' Circuit High Input (Bank 2)
P0394....Camshaft Position Sensor 'B' Circuit Intermittent (Bank 2)
Remember that these Automotive DTC trouble codes are just a starting point, further diagnostics will be required to find the root cause of the check engine light and the setting of the trouble code
