Actron 9640 Manuel D’Utilisation

This system applies to GM vehicles manufactured from 1996 to 

present. Some GM vehicles in 1994 and 1995 were equipped with 

this system. Refer to “Appendix A - Data Link Connectors". GM 

vehicles manufactured from 2002 to present automatically use 

Global OBD II Diagnostics. 

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If an Error Message displays, make sure the OBD II connector is

securely attached, and the ignition key is ON. Cycle the ignition key to

OFF for 10 seconds, then ON. This may be required to reset the computer.

If required, select YES to try again. If the problem still exists, refer to “Error

Messages” on page 9-2. 

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Specific GM Enhanced functions are defined in this section. Refer to

The Manual Info function, instructs the user what section of the manual to use. 

This section covers GM Enhanced (OBD II) Diagnostics.

Refer to “” on page 4-1 of Global OBDII Diagnostics.

The Read Codes function retrieves Diagnostic Trouble Codes (DTCs) from the 

vehicle’s computer module(s). This function can be performed with the KOEO 

or KOER. These codes cause the computer to illuminate the Malfunction 

Indicator Lamp (MIL) when an emission-related  or driveability fault occurs. The 

MIL is also known as the “service engine soon” or “check engine” lamp. 
The GM Enhanced reads DTC’s from the engine or powertrain module (ENG), 

Transmission Module (Trans), or Transfer Case Module (XFER). 

TRANS Hist P1800  
TCM Power
Control Relay
Circuit Open

XFER B2725  
Active Trnsfr Case
Mode Switch Malf

Transmission Module

Transfer Case Module