Test Description

The numbers below refer to the step numbers in the diagnostic procedure.

1. 2
   
   Lack of communication may be due to a malfunction of the serial data circuit, the control module, or the scan tool. The specified procedures in Data Link Communications will determine the particular condition.
2. 5
   
   This step stores the PCM DTC information into the scan tool memory. Review the captured information at the end of the diagnostic procedure in order to catch the next DTC in the event there are multiple DTCs stored. Use this information in order to determine how frequently and how recently the DTC set. This information and other operating conditions when the DTC set may help diagnose an intermittent condition. Capturing the stored information preserves data that the PCM loses when the following occurs:
   • When you are instructed to clear the DTCs.
   • PCM connectors are disconnected.
   • PCM is replaced during a diagnostic procedure or a repair procedure.
3. 6
   
   The presence of DTCs which begin with "U", indicate that some other control module is not communicating. Following the specified procedure will gather all the available information before you perform the tests.
4. 8
   
   If there are other control modules with DTCs set, refer to the DTC list. The DTC list directs you to the appropriate diagnostic procedure.

   If the control module stores multiple powertrain DTCs, diagnose the DTCs in the following order:

   • Component level DTCs, such as sensor DTCs, solenoid DTCs, and relay DTCs. Diagnose the multiple DTCs within this category in numerical order. Begin with the lowest numbered DTC, unless the diagnostic table directs you otherwise.
   • System level DTCs, for example, misfire DTCs, fuel trim DTCs, and catalyst DTCs.

5. 10
   
   This step is for areas that have inspection and maintenance testing procedures for emissions testing. Use this step if the testing facility found one or more I/M system statuses that did not set.