On-Board Diagnostics System - Subaru 2002 Impreza Service Manual

ON-BOARD DIAGNOSTICS SYSTEM
Automatic Transmission
Shift solenoid 2
2-4 brake timing solenoid
3. On-board Diagnostics System
A: FUNCTION
The on-board diagnostics system detects and stores in the form of a code a fault that has occurred
in any of the following input and output signal systems.
AT load signal circuit
-
Torque control signal circuit
-
I
Rear vehicle speed sensor
I
Transfer duty solenoid
I
Low clutch timing solenoid
I
ON
OFF
Abnormal
ON
OFF
I
Front vehicle speed sensor
1
ATF temperature sensor
1
Torque converter turbine speed sensor
I
2 secs
_ - _ _ _ _ - - - _
0.3secs
-
4
-
- -
4
-
2 secs
- - - _ - - - - - -
-
-
4
0.3secs
I I
I
Throttle position sensor
I
Engine speed signal circuit
-
I I
I
Shift solenoid 1
I
Line pressure duty solenoid
-
I
-
I
Lock-up duty solenoid
1
2-4 brake duty solenoid
I
If a fault has been detected, the system tells the fault by causing the AT OIL TEMP warning light
to operate as follows:
0
Repeated flashing at 4 Hz frequency ... Errors such as battery trouble
-o-Repeated flashing at 2 Hz frequency ... No faults in the system
0
Flashing at different intervals and frequencies
...
Diagnostic trouble codes of corresponding
faults
0
Continued illumination of light ... Fault in inhibitor switch, idle switch, or wiring
B: OPERATION OF AT OIL TEMP WARNING LIGHT
On starting the engine, the AT OIL TEMP warning light illuminates and then goes out as shown in
the "Normal" diagram below.
If any problem exists, the light continues flashing as shown in the "Abnormal" diagram below.
Engine starts
I -
Flashes
S3H0227B
AT-34