Actron 9640 user manual List 1I/M Readiness ` 2Read Codes 3Pending

GM Enhanced (OBD II) Diagnostics

Not all GM vehicles support DTC status. Some only use the Global OBDII Read Codes command. For a description of these screens, refer to the Global OBDII section of the manual.

•History Codes — intermittent codes placed in the vehicle’s memory when the trouble originally occurred, and will remain there even if the trouble has been corrected. If no trouble after 50 engine warm-up cycles, the DTC will be erased.

•Current Codes — codes transmitted through the PCM’s data stream when a trouble condition is active and cannot be erased. The problem must be repaired to remove the DTC.

•Intermittent Codes — indicates the current code has been set at least once but possibly not enough to cause a history code to be stored.

•Pending Codes - These are codes that are developing, but are not quite a Current Code.

In GM Enhanced OBD II, if DTCs are present, then three conditions (or statuses) may accompany each DTC definition.

GM Code Types:

•MIL (Malfunction Indicator Lamp): REQUESTED or NOT REQUESTED An emissions-related DTC is requesting the MIL (Check Engine/Service Engine Soon) to be ON.

5	• Since IGN (ignition): PASS, FAIL, P/F, or NOT RUN
	Provides the DTC status during this power-up. P/F (Pass/Fail) indicates the
	PCM detected the DTC that passed and failed at least once during this
	power-up cycle. NOT RUN means the PCM has not tested for the condition
	that set the DTC during this power-up cycle.
	• Since Clear: PASS, FAIL, P/F, or NOT RUN
	Provides the DTC status since the last time the codes were erased.
	P/F indicates the PCM test that detected the DTC passed and failed at least
	once since the last Erase Code. NOT RUN means the PCM has not tested
	for the condition that set the DTC since the last Erase Code.
	Select Read Codes and press ENTER. GM Function	List	?
	1)I/M Readiness
	` 2)Read Codes		[
	3)Pending	Codes	~

The Scan Tool displays the DTCs or a message stating SYSTEM PASS: NO CODES FOUND. Scroll down to view the DTCs or press the BACK key to return

to the GM Function List.

System Pass:	DTCs Found: 13
No Faults Detected.	Use [ To View DTCs
	Write Down Codes
~	For Reference	~

5 – 12 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •