DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Check
4re there holes or loose bolts
in exhaust system?
4re there holes, loose bolts or
lisconnection of hose on air
ntake system?
s
fuel pressure between 284
md 314 kPa (2.9
-
3.2 kgl
:m2,
41
-
46 psi)?
~
AA:DTC
PO172
-
FUEL TRIM MALFUNCTION (NF TOO RICH)
-
DTC DETECTING CONDITION:
Two
consecutive driving cycles with fault
TROUBLE SYMPTOM:
Erroneous idling
Engine stalls.
Poor driving performance
CAUTION:
After repair
or
replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(D0HC TURBO)-
49, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(D0HC TURBO)-46, Inspec-
tion Mode.>.
Yes No
Repair exhaust
system.
Repair air intake
system.
Go
to step
4.
Go
to step
2.
Go
to step 3.
Repair the follow-
ing items.
Fuel pressure
too
high
Clogged fuel
return line or bent
hose
Fuel pressure too
low
Improper fuel
pump discharge
Clogged fuel
Step
CHECK EXHAUST SYSTEM.
!
CHECK
AIR
INTAKE SYSTEM.
I
CHECK FUEL PRESSURE.
Warning:
+lace
“NO
FIRE” signs near the working
area.
*Be careful not to spill fuel on the floor.
1)Release fuel pressure.
(1) Disconnect the connector from fuel
pump relay.
(2) Start the engine and run it until it stalls.
(3) After the engine stalls, crank it for five
more seconds.
(4) Turn the ignition switch to
OFF.
2)Connect the connector to fuel pump relay.
3)Disconnect the fuel delivery hose from fuel
filter, and connect fuel pressure gauge.
4)lnstall the fuel filler cap.
5)Start the engine and idle while gear position
is neutral.
6)Measure the fuel pressure while disconnect-
ing pressure regulator vacuum hose from
intake manifold.
Warning:
Before removing the fuel pressure gauge,
release fuel pressure.
NOTE:
If
fuel pressure does not increase, squeeze fue
return hose
2
to
3
times, then measure fue
Dressure aaain.
EN(D0HC TURBO)-I53
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