Cutlass V6-191 3.1L VIN M SFI (1998)
Body Function Controller: Reading and Clearing Diagnostic Trouble Codes
With Scan Tool
The procedure for reading diagnostic trouble code(s) is to use a diagnostic scan tool. Read Diagnostic Trouble Codes Using a Tech 1, Tech 2 or Other
Scan Tool.
When reading DTC(s), follow instructions supplied by tool manufacturer.
Without Scan Tool
A scan tool must be used to retrieve DTCs from the PCM memory. DTCs can no longer be retrieved by grounding terminals "A" to "B" at the Data Link
Connector (DLC). This also eliminates the PCM function of flashing Code 12. The use of a Tech 1 scan tool or equivalent will be needed to obtain both
current and history DTCs.
Failure to follow this step could result in unnecessary repairs.
With Scan Tool
NOTE: Only clear DTC's when instructed to do so. All of the diagnostic data that was saved along with the DTC will also be erased when the code is
cleared.
To clear Diagnostic Trouble Codes (DTCs), use the diagnostic scan tool, "clear DTCs" or "clear info" function.
When clearing DTCs follow instructions supplied by the tool manufacturer.
To Clear DTCs From Memory:
^
Use a scan tool (recommended) Or
^
Ignition OFF for at least 10 seconds,
^
Disconnect the negative battery cable for 30 seconds (clears status flags).
Notice: Clearing the PCM DTC memory by disconnecting the battery will clear all PCM memories. Since some operations (particularly IAC valve idle
control) are learned, it may be necessary to partially depress the accelerator pedal when re-starting the engine after PCM memory is cleared. It may also
be necessary to release the accelerator pedal very slowly when first returning to idle, to prevent a stall. This will allow the PCM to re-learn Idle Air
Control (IAC) valve position. Learned operations may be restored by normal driving.
Without Scan Tool
NOTE: Only clear DTC's when instructed to do so. All of the diagnostic data that was saved along with the DTC will also be erased when the code is
cleared.
A scan tool should be used to clear diagnostic trouble codes. When a scan tool is not available, DTCs can also be cleared by disconnecting one of the
following sources for at least thirty (30) seconds:
NOTE: When codes are cleared in the following manner, a short period of poor driveablity could result while the processor goes through a relearning
process.
Caution: To prevent system damage, the ignition key must be "OFF" when disconnecting or reconnecting battery power.
^
The power source to the control module. Examples: fuse, pigtail at battery PCM connectors etc.
^
The negative battery cable. (Disconnecting the negative battery cable may result in the loss of other on-board memory data, such as preset radio
tuning).
Notice: Since some operations (particularly IAC valve idle control) are learned, it may be necessary to partially depress the accelerator pedal when
re-starting the engine after PCM memory is cleared. It may also be necessary to release the accelerator pedal very slowly when first returning to idle, to
prevent a stall. This will allow the PCM to re-learn Idle Air Control (IAC) valve position. Learned operations may be restored by normal driving.
