DTC Generation, Diag. Tr. Code/Fault Counter

For certain diagnostic trouble codes, the transmission control module's fault handling subroutine includes a fault counter in addition to determining fault status. This applies to the diagnostic trouble codes that can cause the CHECK GEARBOX lamp to light up.

When the transmission control module's fault handling subroutine decides during the drive cycle that a fault is present, the fault counter is set at 40 and the CHECK ENGINE (MIL) and CHECK GEARBOX lamps light up. If the fault clears up by itself, that is to say the following drive cycles cause the transmission control module to decide that no fault is present, the fault counter Starts counting down at the rate of 1 unit per drive cycle.
A drive cycle starts when the ignition switch is turned to the ON position and ends when it is turned to the OFF position.

When the fault counter reaches 37, the CHECK ENGINE (MIL) and CHECK GEARBOX lamps go out but the diagnostic trouble code still remains stored in the memory. When the fault counter reaches 0 the diagnostic trouble code disappears.

Diagnostic trouble codes for which the fault counter is not set remain stored in the memory until cleared by the ISAT scan tool command "CLEAR FAULT CODES".