Diagnostic Trouble Codes & Fault Codes

Check Engine light, diagnostic trouble codes, fault code problems

Check Engine Light & Diagnostic Trouble Code Articles:

Check Engine Light OnBoard Diagnostics
More on Check Engine Lights & Fault Code Diagnostics
Ford P0171 & P0174 Lean Codes
Other Warning Lights (TEMP, OIL, ALT/GEN, BRAKES, ABS, AIR BAGS, etc.)
Scan Tool Diagnostics
Keeping Scan Tools Up-To-Date
Decoding Onboard Diagnostics
TROUBLE CODES (Look up OBD II Fault Codes)
Understanding OBD II Driveability & Emissions Problems
Zeroing in on OBD II Diagnostics
Controller Area Network (CAN) Diagnostics
Troubleshooting Intermittent Engine Problems
Troubleshooting Engine Problems wtih Temperature
More On Investigating Intermittent Engine Stalling Problems
OBD II Diagnostic Tips
Mode 06 Onboard Diagnostics
Help with DTC P0300 Random Misfire Codes
Troubleshooting a P0420 Catalyst Fault Code

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For Sensor & PCM Related Problems Click Here

For Emission Problems Click Here

For Fuel Related Problems Click Here

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Diagnostic Trouble Code (DTC) Finder

Trouble Code Diagnosis

This page contains links to articles on www.AA1Car.com that deal with diagnostic trouble codes (DTC), fault codes, and onboard diagnostics using scan tools and scanner software.

Computerized engine control systems have the self-diagnostic capability to detect faults that may affect engine performance and emissions. When a fault is detected, the computer will store a diagnostic trouble code in its memory and illuminate the Check Engine Light or Malfunction Indicator Lamp (MIL). On older vehicles (mostly pre-1996), the computer can be put into a special diagnostic mode by grounding certain terminals on a diagnostic connector. This will trigger the manual flash codes to display. The Check Engine Light or other lights will then flash out the fault code. On newer vehicles (1996 and up with OBD II), a code reader or scan tool must be plugged into the diagnostic connector to read and erase codes.

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AA1Car Diagnostic Help
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OBD2HELP.com
Random-Misfire.com
Scan Tool Help
TROUBLE-CODES.com