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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.
Chrysler Powertrain Codes P1100 to P1399
Chrysler Powertrain Codes P1400 to P1899
Ford Powertrain Codes P1000 to P1299
Ford Powertrain Codes P1300 to P1499
Ford Powertrain Codes P1500 to P1699
Ford Powertrain Codes P1700 to P1999
GM Powertrain Codes P1000 to P1299
GM Powertrain Codes P1300 to P1499
GM Powertrain Codes P1500 to P1699
GM Powertrain Codes P1700 to P1899
Controller Area Network (CAN) Codes
Check Engine Light On? Got a Trouble Code and Need Help Now?Want a good reference program for looking up trouble codes off-line?
DTC Code Finder contains all the fault codes on this website in an easy-to-use format. Software can be downloaded to any Windows PC.
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Click on the image above for more details and ordering information
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