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Isuzu Trooper (1998-2002 year). Manual - part 464

6E–226

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

DTC P0175 – Fuel Trim System Rich Bank 2

(Cont'd)

Step

Yes

Value(s)

Action

Visually and physically inspect the air intake duct for
collapse or restriction and repair if necessary.

Did your inspection reveal a problem requiring repair?

—

Verify repair

Go to

Step 8

Inspect the MAF sensor inlet screen for damage or for
the presence of foreign objects which may partially
block air flow through the screen and correct any
problem found.

Did your inspection of the MAF sensor reveal a
condition requiring repair or replacement?

—

Verify repair

Go to

Step 9

Start the engine and note the idle quality.

Is a low or unsteady idle being experienced?

—

Go to

Step 10

Go to

Step 11

1. Turn the ignition off and physically inspect the

throttle body bore, throttle plate, and IAC passages
for coking and foreign objects.

2. If a problem was found, repair as necessary.

Did your inspection reveal a condition requiring repair?

—

Verify repair

Go to

Step 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?

—

Verify repair

Go to

Step 12

1. Ignition “ON”, engine “OFF”.
2. 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?

Minimum 8%

Maximum

92%

Go to

Step 13

Go to

Step 21

1. Disconnect the MAF sensor electrical connector.
2. Operate the vehicle in “closed loop” while

monitoring the “BANK 2 L.T. FUEL TRIM” and
“BANK 2 S.T. FUEL TRIM” display on the Tech 2.

Did both values change to near the specified value?

Go to

Step 22

Go to

Step 14

1. Perform the “Fuel System Pressure Test”.
2. If Fuel System Pressure Test isolates a problem,

repair as necessary (refer to

Engine Fuel or Fuel

Metering System).

Did the Fuel System Pressure Test isolate a condition
requiring repair?

—

Verify repair

Go to

Step 15

1. Ignition “ON”, engine “OFF”.
2. Connect a test light between the harness connector

terminals of canister purge solenoid.

Is the test light on?

—

Go to

Step 16

Go to

Step 19

Check for short to ground in the wire (YEL/RED)
between the canister purge solenoid and PCM terminal
S-48.

Was there a short to ground?

—

Go to

Step 17

Go to

Step 18

6E–227

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0175 – Fuel Trim System Rich Bank 2

(Cont'd)

Step

Yes

Value(s)

Action

Repair the short to ground.

Is the action complete?

—

Verify repair

—

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed. Refer to

On-Vehicle Service in

Powertrain Control Module and Sensors for
procedures.

And also refer to the latest Service Bulletin.

Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.

Is the action complete?

—

Verify repair

—

1. Perform the “Injector Balance Test”.
2. If the Injector Balance Test isolates a problem,

repair as necessary (refer to

Fuel Metering

System).

Did the Injector Balance Test isolate a problem
requiring repair?

—

Verify repair

Go to

Step 20

1. Remove and visually/physically inspect the Bank 2

HO2S 1 for silicon contamination. This will be
indicated by a powdery deposit on the portion of the
HO2S that is exposed to the exhaust stream.

2. If contamination is evident on the Bank 2 HO2S 1,

replace the contaminated sensor.

Did the sensor require replacement?

—

Verify repair

Check the

Procedure

Refer to

Diagnostic

Aids

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?

—

Verify repair

—

Replace the MAF sensor.

Is the action complete?

—

Verify repair

—

6E–228

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0201 Injector 1 Control Circuit

D06R200014

Circuit Description

The powertrain control module (PCM) has six individual
injector driver circuits. Each controls an injector. When a
driver circuit is grounded by the PCM, the injector is
activated. The PCM monitors the current in each driver
circuit. The voltage on each driver is monitored to detect
a fault. If the voltage is not what the PCM expects to
monitor on the circuit, a DTC is set. This DTC is also set if
an injector driver is shorted to voltage or if there is an open
circuit.

Conditions for Setting the DTC

The battery voltage is more than 9 volts.

Engine speed is more than 700 rpm.

The engine is turning, determined by 58X crankshaft
position input signal.

The injector voltage does not equal the ignition voltage
when the injector is commanded “OFF” or the injector
voltage does not equal 0 volts when the injector is
commanded “ON”.

The above conditions are met for 5 seconds.

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

Conditions for Clearing the MIL/DTC

The PCM will turn “OFF” the MIL on the third
consecutive trip cycle in which the diagnostic has been
run and the fault is no longer present.

A history DTC P0201 will clear after 40 consecutive
warm-up cycles occur without a fault.

DTC P0201 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

An injector driver circuit that is open or shorted to voltage
will cause a DTC P0201 to set. It will also cause a misfire
due to an inoperative injector. A misfire DTC will also be
set indicating which cylinder is inoperative.
Long term and short term fuel trims that are excessively
high or low are a good indication that an injector is faulty.
Use Fuel Injector Coil Test Procedure to check for faulty
injectors.

6E–229

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Test Description

The number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. This step determines if DTC P0201 is the result of a

hard failure or an intermittent condition.

5. A special injector test connector is provided so that

the injectors can be electrically tested without
removal of the manifold. The test connector can be
identified by the blue connector lock which is
tethered to the wiring harness. If the light for
cylinder 1 is “ON” steady before cranking the engine
as well as while cranking the engine, then the
injector driver circuit is shorted to ground.

If the test light blinks while cranking, the PCM and
the wiring to the injectors are OK. The Fuel Injector
Coil Test Procedure will check if the injectors are
faulty.

R321054

7. Because the test light was “ON” steady, voltage to

the injector is OK, but the driver circuit is grounded
at all times. This step determines if the circuit is
shorted to ground or the PCM is faulty.

9. The reading should be about 12-14

10.Locating the open in the harness or in the injector

will require removal of the manifold to provide
access.

DTC P0201 – Injector 1 Control Circuit

Step

Action

Value(s)

Yes

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go to

OBD

System

Check

Will the engine start?

—

Go to

Step 3

Go to

Engine

Cranks But

Will Not Run

chart

1. Install the Tech 2. Clear the DTC.
2. Idle the engine for one minute.

Does DTC P0201 reset?

—

Go to

Step 5

Go to

Step 4

1. Review the Freeze Frame data with the ignition

“ON” and the engine “OFF” and note the
parameters.

2. Operate the vehicle within the Freeze Frame

conditions as noted.

Does P0201 reset?

—

Go to

Step 5

Check the

Procedure Go

Diagnostic

Aids

1. Engine “OFF”.
2. Disconnect the injector connector.
3. Install an injector test light J-39021-65 on the

injector test connector.

4. Crank the engine and note the light.

Does the injector test light blink?

—

Go to

Fuel

Injector Coil

Test

Procedure

Go to

Step 6

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