21
Self-Test Part 5: Evaluate/Erase Continuous
Memory Codes.
Do this Part if “Continuous Memory”
codes (other than an 11 or 111 pass
code) were received during SELF-TEST
PART 2: Key On Engine Off (KOEO)
and, all other Parts of the Self-Test
procedure have been completed.
• Continuous Memory codes come
from faults which occurred in the past.
The problem may still be present, or it
may have gone away. Regardless, the
codes will remain in stored in
computer memory (for retrieval during
Self-Test Part 2) until:
• The codes are erased using the
procedure detailed later in this part.
or,
• Power is removed from the computer
for more than a few minutes. (NOTE:
The KAPWR circuit supplies vehicle
battery power to the computer
memory when the ignition key is off.)
or,
• The problem goes away and does not
reappear. After at least 40 engine
warm-up cycles (depends upon
vehicle) the code will automatically be
erased from computer memory if the
problem stays away during that time.
What to Do:
1) Look at the list of Continuous
Memory codes obtained during Self-
Test Part 2: Key On Engine Off
(KOEO).
2) Previous repairs may have eliminated
the causes of some (or all) of these
codes!
3) Disregard codes which are related to
repairs already made. For example, if
repairs were made to the Engine
Coolant Temperature (ECT) sensor
circuit as the result of a KOEO code,
then a Continuous Memory code 21
(ECT signal voltage too high) would
be disregarded.
4) If any codes remain, refer to vehicle
service manual for Continuous
Memory code troubleshooting charts
and repair procedures.
5) Erase Continuous Memory codes
after all repairs have been made.
Erasing Continuous Memory
Codes
1) Verify Ignition Key is in OFF
Position.
2) Put Code Scanner HOLD/TEST
Switch in HOLD Position.
3) Turn Ignition Key to ON Position
but DO NOT START THE ENGINE.
4) Put Code Scanner HOLD/TEST
Switch in TEST Position.
• This starts the normal KOEO Self-
Test.
WARNING: Stay away from the
radiator cooling fan! It may turn on
momentarily. (On certain vehicles
with electrically operated fans.)
5) Wait for the STO Light to Start
Blinking (Codes are Being Sent).
6) Put Code Scanner HOLD/TEST
Switch in HOLD Position.
• The switch must be moved during
the time the STO light is blinking
(the time period when codes are
being sent).
7) The “Continuous Memory” Codes
are Now Erased.
8) Turn Ignition Key to OFF Position.
9) Disconnect Code Scanner.
