Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Service manual - part 771

6E–108

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Electric Throttle Control (ETC) System Check

D06R200033

6E–109

TROOPER 6VE1 3.5L 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.

6E–110

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

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

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

6E–111

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Electric Throttle Control (ETC) System Check

  (Cont'd)

Step

No

Yes

Value(s)

Action

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

8

1. Warming up the engine until the ECT rise at 80

°

C

2. Ignition “OFF”.
3. Insall the Tech 2.
4. Ignition “ON” but not engine run.
5. Check the value for APS and TPS.

NOTE: The value check of TPS must be performed in
less than 15 seconds.

Was a problem found?

Closed

throttle APS1

= 11

∼

15%

APS2 =

85

∼

89%

APS3 =

85

∼

89%

TPS1 =

6

∼

12% TPS2

= 88

∼

94%

Wide open

throttle APS1

= 85

∼

89%

APS2 =

11

∼

15%

APS3 =

32

∼

36%

TPS1 =

79

∼

83%

TPS2 =

19

∼

23%

Go to 

Step 9

System O.K.

9

1. Replace the faulty sensor.
2. Re–check the value for APS and TPS Refer to the

procedure in step 8.

Was the problem found?

—

Go to 

Step 10

Verify repair

10

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 letest Service Bulletin.

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

—

Verify repair

—