The DTC value will help you narrow down the specific component or module in question. A DTC has a standardized format that can be interpreted as follows:
The first part of the DTC is the Alpha Designator. The alpha
designator can be:

B - Body electronics (i.e., door and hood latches)
C - Chassis (i.e., traction control or ABS)
P - Powertrain (i.e., engine, transmission, or engine support components)
U - Network communications for the different control models

The second part of the DTC, is a three or four-digit numerical series. The OBD-II specification has reserved the first 1,000 entries for a core set that are uniformly implemented across all vehicle manufacturers. DTCs after the core set are available for manufacturer specific uses.

Type of Code will be 0 for the core set, or a value of 1 - 9 for manufacturer specific codes. The Indicated System and Specific Code Number further narrow down the code to a specific component or system.

Emissions Related DTCs

• The Malfunction Indicator Lamp (MIL) will be illuminated as soon as the error occurs.
• The ECM will record operating conditions at the time the diagnostic fails. The information will be stored in the freeze frame and failure records buffers.
  A history DTC is stored.

Action Taken When the DTC Sets – Type B (or E) 

• The Malfunction Indicator Lamp (MIL) will be illuminated after 2 (or 3) valid driving cycles.
• The ECM will record operating conditions at the time the diagnostic fails. The information will be stored in the freeze frame and failure records buffers.
• A history DTC is stored.

Conditions for Clearing the MIL/DTC – Type A or Type B (or E) 

• The MIL will turn off after four consecutive driving cycles in which the diagnostic runs without a fault.
• A history DTC will clear after 40 consecutive warm up cycles without a fault.
• DTC(s) can be cleared by using the scan tool.

Non–Emissions Relatedelated DTCs

Action Taken When the DTC Sets – Type Cnl 

• The Malfunction Indicator Lamp (MIL) will not illuminate.
• The ECM will record operating conditions at the time the diagnostic fails.
• The information will be stored in the freeze frame and failure records buffers.

• A history DTC will clear after 40 consecutive warm up cycles without a fault.
• DTC(s) can be cleared by using the scan tool.

Conditions for Clearing the DTC – Type Z 
This DTC is available in the control module software, but has been disabled, or turned OFF. In this case, the diagnostic does not run, no DTCs are stored, and the MIL does not illuminate.

CLEARING TROUBLE CODES

Important: Do not clear DTCs unless directed to do so by the service information provided for each diagnostic procedure.

When DTCs are cleared, the Freeze Frame and Failure Record data which may help diagnose an intermittent fault will also be erased from memory. If the fault that caused the DTC to be stored into memory has been corrected, the Diagnostic Executive will begin to count the warmup cycles with no further faults detected, the DTC will automatically be cleared from the engine control module (ECM) memory.

To clear DTCs, use the diagnostic scan tool.

Notice:

To prevent ECM damage, the key must be OFF when disconnecting or reconnecting the power to the ECM (for example battery cable, ECM pigtail connector, ECM fuse, jumper cables, etc.). When the ECM sets a Diagnostic Trouble Code (DTC), the Malfunction Indicator Lamp (MIL) lamp will be turned on only for type A, B and E but a DTC will be stored in the ECM s memory for all types of DTC. The DTC will stay in the ECM s memory until cleared by scan tool. DTCs should be cleared after repairs have been completed. Some diagnostic tables will tell you to clear the codes before using the chart. This allows the ECM to set the DTC while going through the chart, which will help to find the cause of the problem more quickly.