Isuzu Trooper (1998-2002 year). Manual - part 434

6E–106

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Fuel System Electrical Test

  (Cont'd)

Step

No

Yes

Value(s)

Action

11

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 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

—

12

1. Reconnect the fuel pump relay.
2. Disconnect the fuel pump electrical connector at the

fuel tank.

3. Using a test light connected to ground, probe the

fuel pump feed wire (harness side).

4. Command the fuel pump “ON” with a Tech 2.

Did the light illuminate for 2 seconds?

—

Go to 

Step 15

Go to 

Step 13

13

1. Honk the horn to verify that the horn relay is

functioning.

2. Substitute the horn relay for the fuel pump relay.
3. Leave the test light connected as in step 12.
4. Command the fuel pump “ON” with the Tech 2.

Did the test light illuminate for 2 seconds when the fuel
pump was commanded “ON”?

—

Go to 

Step 17

Go to 

Step 14

14

1. Re-connect the horn relay in its proper location.
2. Check for a short circuit, blown fuse or open circuit

between the relay and the fuel tank.

Is the action complete?

—

Verify repair

—

15

1. With the fuel pump electrical connector at the fuel

tank disconnected, connect a test light between the
feed wire and the ground wire (harness side).

2. Command the fuel pump “ON” with a Tech 2.

Did the test light illuminate for 2 seconds?

—

Go to 

Step 18

Go to 

Step 16

16

Repair the open circuit in the fuel pump ground wire.

Is the action complete?

—

Verify repair

—

17

1. Re-connect the horn relay in its proper location.
2. Replace the fuel pump relay.

Is the action complete?

—

Verify repair

—

18

Replace the fuel pump.

Is the action complete?

—

Verify repair

—

6E–107

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Electric Throttle Control (ETC) System Check

D06R200033

6E–108

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Circuit Description

D

The powertrain control module (PCM) controls
engine speed by adjusting the position of the throttle
control valve (DC motor). The throttle motor is a DC
motor driven by one coil. The PCM applies current to
the DC motor coil in PWM (%) to adjust the throttle
valve into a passage in the throttle body to allow air
flow. This method allows highly accurate control of
engine speed and quick response to changes in
engine load.

D

The acceleration position (AP) sensor circuit provides
a voltage signal relative to acceleration pedal angle.
The acceleration pedal angle will vary about 13% at
idle position to about 87% at wide open
throttle(WOT).
APS signal is used to determine which DC motor will
adjust throttle position.
After the APS signal has been processed by the
PCM, it will command DC motor to allow movement of
throttle position.

Diagnostic Aids

D

An intermittent may be caused by a poor connection,
rubbed-through wire insulation or a wire broken inside
the insulation. Check for poor connections or a
damaged harness. Inspect the PCM harness and
connector for improper mating, broken locks,
improperly formed or damaged terminals, poor
terminal-to-wire connection, and damaged harness.

D

Throttle body – Check for objects blocking the DC
motor or throttle bore, excessive deposits in the ETC
passage and on the valve spring, and excessive
deposits in the throttle bore and on the throttle valve
plate.

D

Acceleration pedal – Check for objects blocking the
AP sensor or pedal arm with spring, excessive
deposits in the acceleration pedal arm and on the
acceleration pedal and lacking the pedal stopper
rabber.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2. Visually/physically inspect for the following throttle

valve conditions.

3. Visually/physically inspect for the following

acceleration pedal conditions.

5. Check the following circuits for throttle valve and DC

moter. Check the following TP sensor resistance
and DC motor. 

6. Check the following circuits for acceleration pedal.

Check the following AP sensor resistance.

7. Following DTC: Error for ETC system.

Electric Throttle Control (ETC) System Check

 

Step

Action

Value(s)

Yes

No

1

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

—

Go to 

Step 2

Go to 

OBD

System

Check

2

Visually/physically inspect for the following conditions:

D

Throttle body tampering. 

D

Restricted intake throttle system. Check for a
possible collapsed air intake duct, restricted air
filter element, or foreign objects blocking the air
intake system. 

D

Throttle body: Check for objects blocking the
throttle passage or throttle bore, excessive
deposits in the throttle passage and on the throttle
valve, and excessive deposits in the throttle bore
and on the throttle plate. 

D

Throttle body with lever: When check for objects
to send round the throttle spring lever that lever is
smooth movement by less than 9 l·bm{1.0 N·m},
and spring lever has not excessive play. 

D

Throttle function: Check for the throttle function.
When ignition switch “ON” that throttle lever is
smooth operated by step on the acceleration
pedal.

Did any of the above require a repair?

—

Refer to

appropriate

section for

on-vehicle

service

Go to 

Step 3

6E–109

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Electric Throttle Control (ETC) System Check

  (Cont'd)

Step

No

Yes

Value(s)

Action

3

Visually/physically inspect for the following conditions:

D

Acceleration pedal tampering. 

D

Acceleration pedal : Check for objects blocking
the spring or pedal arm. 

D

Acceleration pedal : For check for objects to move
the acceleration pedal that pedal is smooth
movement, and acceleration pedal arm has not
excessive play. 

Did any of the above require a repair?

—

Refer to

appropriate

section for

on-vehicle

service

Go to 

Step 4

4

1. Check for a poor connection at the throttle body

harness connector. 

2. Check for a poor connection at the acceleration

position sensor harness connector. 

3. If a problem is found, replace faulty terminals as

necessary. 

Was a problem found?

—

Verify repair

Go to 

Step 5

5

Check the following circuits for an open, short to
voltage, short to ground, or poor connection at the
PCM:

D

Throttle position sensor 1 circuit. 

D

Throttle position sensor 2 circuit. 

D

Throttle DC motor circuit. 

D

Throttle position sensor resistance.

D

Throttle DC motor resistance. 

If a problem is found, repair as necessary.

Was a problem found?

TPS, DC

mortor 1–7k

W

TPS, DC

mortor

change

resistance

0.3–100

W

Verify repair

Go to 

Step 6

6

Check the following circuits for an open, short to
voltage, short to ground, or poor connection at the
PCM:

D

Acceleration position sensor 1 circuit.

D

Acceleration position sensor 2 circuit.

D

Acceleration position sensor 3 circuit.

D

Acceleration position sensor resistance.

If a problem is found, repair as necessary.

Was the prblem found?

Vcc–GND

AP1 2.6–4k

W

AP2 2.6–4k

W

AP3

4.2–6.4k

W

Verify repair

Go to 

Step 7

7

Following below the DTCs stored: P1120, P1220,
P1221, P1271, P1272, P1273, P1275, P1280, P1285,
P1514, P1515, P1516, P1523

—

Go to

applicable
DTC table

Go to 

Step 8