Isuzu 1999 RODEO Workshop Manual page 805

6E1–178 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
DTC P0172 – System Too Rich (Bank 1) (Cont'd)
Step
10 1. Perform the "Idle Air Control (IAC) Valve Check."
2. If a problem is found, repair as necessary.
Did the test isolate a problem requiring repair?
11 1. Disconnect the vacuum hose from the fuel pressure
regulator and inspect the hose for the presence of
fuel.
2. If fuel is present in the vacuum hose, replace the
fuel pressure regulator (refer to Fuel Metering
System).
Did the fuel pressure regulator require replacement?
12 Ignition ON engine OFF monitor the TP Angle display
on the Tech 2 while slowly depressing the accelerator
pedal.
Does the TP Angle display increase steadily and
evenly from minimum value at closed throttle to
maximum value at wide–open throttle?
13 1. Perform the "Fuel System Pressure Test."
2. If the test isolates a problem, repair as necessary
(refer to Engine Fuel or Fuel Metering System).
Did the test isolate a problem requiring repair?
14 1. Perform the "Evaporative Emissions Control
(EVAP) Canister Purge Valve Check."
2. If the test isolates a problem, repair as necessary.
Did the test isolate a problem requiring repair?
15 1. Perform the "Injector Balance Test."
2. If the test isolates a problem, repair as necessary
(refer to Fuel Metering System).
Did the test isolate a problem requiring repair?
16 1. Remove and visually/physically inspect the Bank 1
HO2S 1 for silicon contamination. This will be
indicated by a powdery white deposit on the portion
of the HO2S that is exposed to the exhaust stream.
2. If contamination is evident on the Bank 1 HO2S 1,
replace the contaminated sensors.
Did the sensor require replacement?
17 1. Check the TP sensor mounting screws and tighten
or replace them as necessary if they are loose or
missing.
2. If the screws are OK, replace the TP sensor.
Is the action complete?
Action Value(s) Yes
— Verify repair
— Verify repair
Minimum 0%
Maximum
Go to Step
100%
13
— Verify repair
— Verify repair
— Verify repair
— Verify repair
— Verify repair
No
Go to Step
11
Go to Step
12
Go to Step
17
Go to Step
14
Go to Step
15
Go to Step
16
Refer to
Diagnostic
Aids
—