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Isuzu KB P190. Manual - part 579

6E–146

ENGINE DRIVEABILITY AND EMISSIONS

Using the DVM and check the TPS signal circuit.
Breaker box is available:

1. Ignition “Off”, engine “Off”.

2. Install the breaker box as type A. (ECM

disconnected) Refer to 6E-88 page.

3. Disconnect TPS connector.

4. Check the circuit for open, short to sensor ground

or short to ground circuit.

Was the problem found?

Breaker box is not available:

1. Ignition “Off”, engine “Off”.

2. Disconnect the TPS connector and ECM

connector.

3. Check the circuit for open, short to sensor ground

or short to ground circuit.

Was the problem found?

—

Repair faulty

harness and

verify repair

Go to Step 12

Substitute a known good TPS and recheck.
Was the problem solved?

—

Go to Step 11

Go to Step 12

Replace the TPS.
Is the action complete?

—

Verify repair

Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

—

Verify repair

Go to Step 12

Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

—

Verify repair

—

Step

Action

Value(s)

Yes

J1-7

J1-32

Breaker Box

E-86

E60(J1)

E68

ENGINE DRIVEABILITY AND EMISSIONS

6E–147

DIAGNOSTIC TROUBLE CODE (DTC) P0123 THROTTLE POSITION SENSOR

HIGH INPUT

Condition for setting the DTC and action taken when the DTC sets

Circuit Description

The throttle position sensor circuit provides a voltage
signal that changes relative to throttle blade angle. The
signal voltage will vary from below 1 volt at closed
throttle to about 4 volts at wide open throttle (WOT).
The TPS is used by the engine control module (ECM)
for fuel control and most of the ECM-controlled outputs.
If the ECM detect a continuous short voltage in the TPS
or circuit, then a code P0123 will set.

Diagnostic Aids

Check for the following conditions:

• Poor connection at ECM - Inspect harness

connectors for backed-out terminals, improper
mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connection.

• If these codes are also set, it could indicate a

problem with the 5 Volt reference circuit or
components itself.

• Damaged harness - Inspect the wiring harness for

damage, short to ground, short to battery positive and
open circuit. If the harness appears to be OK,
observe the Throttle Position sensor display on the
Tech 2 while moving connectors and wiring
harnesses related to the TP sensor. A change in the
display will indicate the location of the fault.

Code

Type

DTC Name

DTC Setting Condition

Fail-Safe (Back Up)

P0123

Throttle Position Sensor High Input

TPS output voltage is more than 4.9V.

The ECM uses 0% condition as substitute.

6E–148

ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0123 Throttle Position Sensor High Input

Step

Action

Value(s)

Yes

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

—

Go to Step 2

Go to On Board

Diagnostic

(OBD) System

Check

1. Connect the Tech 2.

2. Review and record the failure information.

3. Select “F0: Read DTC Infor By Priority” in “F0:

Diagnostic Trouble Code”.

Is the DTC P0123 stored as “Present Failure”?

—

Go to Step 3

Refer to

Diagnostic Aids

and Go to Step

1. Using the Tech2, ignition “On” and engine “Off”.

2. Select “Clear DTC Information” with the Tech2 and

clear the DTC information.

3. Operate the vehicle and monitor the “F5: Failed

This Ignition” in “F2: DTC Information”.

Was the DTC P0123 stored in this ignition cycle?

—

Go to Step 4

Refer to

Diagnostic Aids

and Go to Step

Check for poor/faulty connection at the TPS or ECM
connector. If a poor/faulty connection is found, repair
as necessary.
Was the problem found?

—

Verify repair

Go to Step 5

Visually check the TPS.
Was the problem found?

—

Go to Step 12

Go to Step 6

Using the DVM and check the TPS.

1. Ignition “Off”, engine “Off”.

2. Disconnect TPS connector.

3. Measure the resistance of TPS.

Does the tester indicate standard resistance as shown
in the following table?

Standard

resistance

Go to Step 7

Go to Step 12

E60(J1)

E68

15 7

Measurement

Terminal

Resistance (

Ω)

1 - 2

Approximately 5.6k

Ω at idle position &

WOT

2 - 3

Approximately 6.0k

Ω at idle position

Approximately 1.7k

Ω at WOT

1 - 3

Approximately 2.3k

Ω at idle position &

WOT

Approximately 6.6k

Ω at WOT

TPS

ENGINE DRIVEABILITY AND EMISSIONS

6E–149

Using the DVM and check the TPS power supply
circuit.

1. Ignition “On”, engine “Off”.

2. Disconnect the TPS connector.

3. Check the circuit for short to voltage circuit.

Was the DVM indicated specified value?

Approximately

5.0V

Go to Step 9

Go to Step 8

Repair the short to voltage circuit between the ECM
and TPS.
Was the problem solved?

—

Verify repair

Go to Step 14

Using the DVM and check the TPS signal circuit.

1. Ignition “On”, engine “Off”.

2. Disconnect the TPS connector.

3. Check the circuit for short to power supply circuit.

Was the DVM indicated specified value?

Less than 1V

Go to Step 10

Repair faulty

harness and

verify repair

Using the DVM and check the TPS ground circuit.

1. Ignition “On”, engine “Off”.

2. Disconnect the TPS connector .

3. Check the circuit for short to power supply circuit.

Was the DVM indicated specified value?

Less than 1V

Go to Step 11

Repair faulty

harness and

verify repair

Step

Action

Value(s)

Yes

E68

E60(J1)

E68

Content .. 577 578 579 580 ..