AUTOMATIC TRANSAXLE DIAGNOSIS
TSB Revision
AUTOMATIC TRANSAXLE
23A-15
A/T DIAGNOSTIC TROUBLESHOOTING STRATEGY
M1231007600243
Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will find most A/T mal-
functions.
1. Gather as much information as possible about the
complaint from the customer.
2. Verify that the condition described by the
customer exists.
3. Check the vehicle for any A/T Diagnostic Trouble
Codes (DTCs).
4. If you can not verify the condition and there are no
DTCs, the malfunction is intermittent. For
information on how to cope with intermittent
malfunctions, refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
− How
to Cope with Intermittent Malfunction
P.00-6
.
5. If you can verify the condition but there are no
DTCs, or the system can not communicate with
scan tool, refer to the Symptom Chart
P.23A-45
.
6. If there is a DTC, record the number of the code,
then erase the code from memory using scan tool.
7. Reconfirm the symptom with a Road Test.
8. If a DTC is set again, go to the Inspection Chart
for Diagnostic Trouble Codes.
9. If a DTC is not set again, the malfunction is
intermittent. For information on how to cope with
intermittent malfunctions, refer to GROUP 00,
How to Use Troubleshooting/Inspection Service
Points
− How to Cope with Intermittent
Malfunction
P.00-6
.
10.After repairs are completed, conduct a Road Test
duplicating the complaint conditions to confirm the
malfunction has been eliminated.
DIAGNOSTIC FUNCTION
M1231022500050
CHECK "N" RANGE LIGHT
The "N" range light flashes once per second if there is an
abnormality in any of the items in the table below which are
related to the A/T system. Check for diagnostic trouble codes if
the "N" range light is flashing once per second.
"N" range light flashing items
• Input shaft speed sensor
• Output shaft speed sensor
• Each solenoid valve
• Gear incorrect ratio
• A/T control relay system
CAUTION
If the "N" range light is flashing twice per second, it means
that the transmission fluid temperature is too high. Stop
the vehicle in a safe place and wait until the "N" range light
switches off.
ON-BOARD DIAGNOSTICS
The powertrain control module (PCM) monitors its
input/output signals (some signals all the time and
others under specified conditions). When an irregular
signal is initially monitored, the PCM decides that a
malfunction has occurred and records the occur-
rence as a diagnostic trouble code. There are 21
diagnostic items. The diagnostic results can be read
with scan tool. Diagnostic trouble codes are kept in
memory by direct battery feed. The codes are
retained in memory even if the ignition switch is in
the "LOCK" (OFF) position. DTCs are not erased
even after the battery terminals and the PCM con-
nector are disconnected. In addition, the diagnostic
trouble code can also be erased by scan tool.
NOTE: If a sensor is disconnected when the ignition
switch is in the "ON" position, a diagnostic trouble
code is stored in memory. In this case, erase the
DTC using scan tool.
The 21 diagnostic items are displayed in numeric
order.
AC209439AC