With Vehicle Control Module (VCM-A)
DIAGNOSISIf a diagnostic chart indicates that a Vehicle Control Module (VCM-A) connection or VCM-A is the cause of a problem and the VCM-A is replaced, but does not correct the problem, one of the following may be the reason.
^ The VCM-A was replaced and not reprogrammed correctly. Refer to EEPROM programming procedure in "On-Vehicle Service."
^ There is a problem with the VCM-A terminal connections - The terminals may need to be removed from the connector in order to check them properly.
^ The VCM-A is not correct for the application - The incorrect components may cause a malfunction and may, or may not, set a Diagnostic Trouble Code (DTC).
^ The problem is intermittent - This means that the problem is not present at the time the system is being checked. In this case refer to Diagnosis by Symptom and make a careful physical inspection of all portions of the system involved. Testing and Inspection
^ Shorted Solenoid, Relay Coil or Harness - Solenoids and relays are turned "ON" and "OFF" by the VCM.A using internal electronic switches called "drivers." Each driver is part of a group of four called "quad-drivers." Failure of one driver can darnage any other driver in the set.
A shorted Solenoid, Relay Coil or Harness will not damage the "quad-drivers" in the VCM-A but will cause the circuit and controlled component to be inoperative. When the circuit fault is not present or has been repaired, the "quad-driver" will again operate in a normal manner due to its fault protected design. If a fault has been repaired In a circuit controlled by a "quad-driver," the original VCM-A should be reinstalled and the circuit checked for proper operation. VCM-A replacement will not be necessary if the repaired circuit or component operates correctly.
NOTE: J 39200 tester provides a fast, accurate means of checking for a shorted coil or a short to battery voltage.