1. Engine Lubrication System
Before troubleshooting, make sure that the engine oil level
is correct and no oil leakage exists.
Trouble Possible cause Corrective action
1. Warning light remains
on.1) Oil pressure switch
failureCracked diaphragm or oil leakage within switch Replace.
Broken spring or seized contacts Replace.
2) Low oil pressureClogged oil filter Replace.
Malfunction of oil by-pass valve of oil filter Clean or replace.
Malfunction of oil relief valve of oil pump Clean or replace.
Clogged oil passage Clean.
Excessive tip clearance and side clearance of oil
pump rotor and gearReplace.
Clogged oil strainer or broken pipe Clean or replace.
3) No oil pressureInsufficient engine oil Replenish.
Broken pipe of oil strainer Replace.
Stuck oil pump rotor Replace.
2. Warning light does not
go on.1) Burn-out bulb Replace.
2) Poor contact of switch contact points Replace.
3) Disconnection of wiring Repair.
3. Warning light flickers
momentarily.1) Poor contact at terminals Repair.
2) Defective wiring harness Repair.
3) Low oil pressureCheck for the same pos-
sible causes as listed in
1.—2)
17
2-4DIAGNOSTICS
1. Engine Lubrication System
1. General
1. GENERAL DESCRIPTION
The on-board diagnostics (OBD) system detects and
indicates a fault in various inputs and outputs of the com-
plex electronic control. CHECK ENGINE malfunction indi-
cator lamp (MIL) in the combination meter indicates occur-
rence of a fault or trouble.
Further, against such a failure or sensors as may disable
the drive, the fail-safe function is provided to ensure the
minimal driveability.
The OBD system incorporated with the vehicles within
this engine family complies with Section 1968.1, California
Code of Regulations (OBD-II regulation). The OBD system
monitors the components and the system malfunction
listed in Engine Section which affects on emissions.
When the system decides that a malfunction occurs, MIL
illuminates. At the same time of the MIL illumination or
blinking, a diagnostic trouble code (DTC) and a freeze
frame engine conditions are stored into on-board com-
puter.
The OBD system stores freeze frame engine condition
data (engine load, engine coolant temperature, fuel trim,
engine speed and vehicle speed, etc.) into on-board com-
puter when it detects a malfunction first.
If the OBD system detects the various malfunctions
including the fault of fuel trim or misfire, the OBD system
first stores freeze frame engine conditions about the fuel
trim or misfire.
When the malfunction does not occur again for three
consecutive driving cycles, MIL is turned off, but DTC
remains at on-board computer.
The OBD-II system is capable of communication with a
general scan tool (OBD-II general scan tool) formed by ISO
9141 CARB.
The OBD-II diagnostics procedure is different from the
usual diagnostics procedure. When troubleshooting OBD-II
vehicles, connect Subaru select monitor or the OBD-II gen-
eral scan tool to the vehicle.
A: ENGINE
1. ENGINE AND EMISSION CONTROL SYSTEM
The Multipoint Fuel Injection (MFI) system is a system
that supplies the optimum air-fuel mixture to the engine for
all the various operating conditions through the use of the
latest electronic technology.
With this system fuel, which is pressurized at a constant
pressure, is injected into the intake air passage of the cyl-
inder head. The injection quantity of fuel is controlled by an
intermittent injection system where the electro-magnetic
injection valve (fuel injector) opens only for a short period
of time, depending on the quantity of air required for one
cycle of operation. In actual operation, the injection quan-
2
2-7ON-BOARD DIAGNOSTICS II SYSTEM
1. General
Diagnostic items
(select monitor FB0)CodeDisplay screen
(FB0)Diagnostic items (select monitor FB1) Display screen (FB1)Ref. to
4-4b
Abnormal stroke sen-
sor and stop light
switch54 PSS & BLSOpen/short circuits of stroke sensor B.SW HARD [T10Y1]
Comparison of stroke sensor and acceleration B.SW SOFT(G) [T10Y2]
Comparison of stroke sensor and stop light switch B.SW SOFT(B) [T10Y3]
Comparison of stroke sensor and pump B.SW SOFT(P) [T10Y4]
Open circuit of stop light switch B.SW SOFT(O) [T10Y5]
Abnormal fluid level
sensor line57 FLUID LEVEL SS Abnormal fluid level sensor line FLUID LEVEL SS [T10Z0]
Abnormal pressure
switch58 PRESSURE SW Abnormal pressure switch PRESSURE SW [T10AA0]
Abnormal TCS1 valve 61 TCS1 VALVE Abnormal TCS1 valve TCS1 VALVE [T10AB0]
Abnormal TCS2 valve 62 TCS2 VALVE Abnormal TCS2 valve TCS2 VALVE [T10AC0]
1. IF THE SELECT MONITOR IS USED FOR
TROUBLESHOOTING, IT IS ADVISED TO FOLLOW
THE PROCEDURE BELOW
1) Activate function FB0 to read the most recent trouble
code and record it.
2) Activate function FB1 to read all trouble codes and
record them.
(If troubles occur in the wheel speed sensor, stop & brake
switch, valve relay or motor system, detailed data on
troubles are displayed by the FB1 function, allowing you to
easily locate points where need repair.)
3) Perform troubleshooting mainly in the FB1 mode.
95
4-4bBRAKES
10. Diagnostic Chart with Select Monitor
