GM OBD1 Systems
CODE RETRIEVAL PROCEDURE
110 3160g
Retrieving and using Diagnostic Trouble Codes (DTCs) for
troubleshooting vehicle operation is only one part of an
overall diagnostic strategy.
Intermittent/History DTCs
Intermittent/History DTCs are stored in the computer's memory for
problems that occur intermittently, or for problems that happened in
the past but are not currently present. Intermittent DTCs may cause
the Malfunction Indicator light to flicker or stay on until the
intermittent malfunction goes away. However, the corresponding
fault code will be stored in memory as a history DTC. If the
malfunction that caused the history DTC to set does not recur within
a predetermined length of time (usually within 40-80 ignition key
start cycles), the computer will automatically erase the related fault
code from its memory.
CODE RETRIEVAL PROCEDURE
Never replace a part based only on the DTC definition.
Each DTC has a set of testing procedures, instructions
and flow charts that must be followed to confirm the
location of the problem. This information is found in the
vehicle's service manual. Always refer to the vehicle's
service manual for detailed testing instructions.
Check your vehicle thoroughly before performing
any test. See BEFORE YOU BEGIN on page 31
for details.
ALWAYS
observe safety precautions whenever working on a
vehicle. See Safety Precautions on page 3 for more
information.
1.
Locate the vehicle's Data Link Connector (DLC). See DATA LINK
CONNECTOR (DLC) on page 109 for connector location.
Some DLCs have a plastic cover that must be removed before
connecting the Scan Tool's cable connector.
2.
Connect the Scan Tool cable (with the
GM Connector Cable Adaptor attached)
to the Scan Tool, then connect the
adaptor to the vehicle’s DLC. Press the
POWER/LINK
button to turn the
Scan Tool ON, then press the
ENTER
button to continue.
An “instructional” message shows
on the Scan Tool’s display.