Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

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System Operation

The Transmission Control Module (TCM) monitors operation of the transmission control system. Some components are monitored continuously, others only during specified operating conditions. When the TCM detects a malfunction lasting longer than a specified period of time the TCM will generate an error code that can be detected at the diagnostic connector.

There are 25 diagnostic items (including normal operation) plus 7 fail safe items that will generate diagnostic codes. The malfunction codes are erased when the vehicle battery is disconnected for more than ten seconds.

If multiple malfunctions occur the diagnostic codes will be sent sequentially beginning with the lowest number code in ascending order with a 2 second pause between each code. A maximum of up to 10 fault codes can be stored in the control module's memory. If the number of stored codes exceeds 10, previously stored codes will be erased, beginning with the oldest code.

If the fail-safe system is activated, the transaxle will be locked in one forward gear while in any of the forward gear positions. This is provided so that the customer can "limp" the vehicle to a repair facility without causing further damage to the transmission.