Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 845

6E–109

3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0122 –TP Sensor Circuit  Low Voltage

  (Cont'd)

Step

No

Yes

Value(s)

Action

10

Check the TP sensor signal circuit for a poor
connection at the TP sensor and replace the terminal if
necessary.

Did the terminal require replacement?

—

Verify repair

Go to 

Step 11

11

Replace the TP sensor.

Is the action complete?

—

Verify repair

—

12

Replace the ECM.

Is the action complete?

—

Verify repair

—

6E–110

3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0123 (Flash DTC=21) TP Sensor Circuit  High

Voltage

060RW077

Circuit Description

The throttle position (TP) sensor circuit provides a voltage
signal that changes relative to throttle blade angle.  The
signal voltage will vary from about 0.6 volts at closed
throttle to about 4.5 volts at wide open throttle (WOT).
The TP signal is one of the most important inputs used by
the Engine Control Module ECM for fuel control and many
of the ECM-controlled outputs.

Conditions for Setting the DTC

D

Ignition SW is ON.

D

The TP sensor voltage more than 4800m volts.

D

Above conditions present for at least 960m second.

Action Taken When the DTC Sets

D

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

D

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

D

The ECM will use a default throttle position based on
mass air flow and RPM.

Conditions for Clearing the MIL/DTC

D

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

D

A history DTC P0123 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D

DTC P0123 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.

Diagnostic Aids

Check for the following conditions:

D

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.

D

Damaged harness – Inspect the wiring harness for
damage.  If the harness appears to be OK, observe the
TP 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.

D

Faulty TP sensor – With the ignition key “ON,” engine
“OFF,” observe the TP sensor display on the Tech 2
while slowly depressing the accelerator to wide open
throttle.  If a voltage over 4.88 volts is seen at any point
in normal accelerator travel, replace the TP sensor.

If DTC P0123 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

Test Description

Number (s) below refer to the step number(s) on the
Diagnostic Chart.

6E–111

3.2L ENGINE DRIVEABILITY AND EMISSIONS

7. Components that share the TP sensor 5 volt reference
“A” circuit include the following device:

DTC P0123 – TP Sensor Circuit High Voltage

 

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

1. Ignition “ON,” engine “OFF.”
2. With the throttle closed, observe the “TP Sensor”

display on the Tech 2.

Is the “TP Sensor” above the specified value?

4.88 V

Go to 

Step 4

Go to 

Step 3

3

1. Ignition “ON,” engine “OFF.”
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records

conditions as noted.

4. Using a Tech 2, monitor “Specific DTC” info for DTC

P0123.

Does the Tech 2 indicate DTC P0123 failed.

—

Go to 

Step 4

Refer to

Diagnostic

Aids

4

1. Disconnect the TP sensor electrical connector.
2. Observe the “TP Sensor” display on the Tech 2.

Is the “TP Sensor” near the specified value?

0 V

Go to 

Step 5

Go to 

Step 6

5

Probe the sensor ground circuit at the TP sensor
harness connector with a test light connected to B+.

Is the test light “ON?”

—

Go to 

Step 7

Go to 

Step 10

6

1. Ignition “OFF,” disconnect the ECM.
2. Ignition “ON,” engine “OFF.”
3. Check for a short to voltage on the TP sensor signal

circuit.

4. If the TP sensor signal circuit is shorted, repair it as

necessary.

Was the TP sensor signal circuit shorted?

—

Verify repair

Go to 

Step 12

7

1. Ignition “ON.”
2. Monitor the “TP Sensor” Tech 2 display while

disconnecting each of the components that share
the 5 volt reference “A” circuit (one at a time).

3. If the “TP Sensor” Tech 2 display changes, replace

the component that caused the display to change
when disconnected.

Does disconnecting any of these components cause
the “TP Sensor” display to change?

—

Verify repair

Go to 

Step 8

8

1. Ignition “OFF,” disconnect the ECM.
2. Ignition “ON,” engine “OFF.”
3. Check for a short to B+ on the 5 volt reference “A”

circuit.

4. If the 5 volt reference “A” circuit is shorted, repair it

as necessary.

Was the 5 volt reference “A” circuit shorted?

—

Verify repair

Go to 

Step 9

9

Check for poor electrical connections at the TP sensor
and replace terminals if necessary.

Did any terminals require replacement?

—

Verify repair

Go to 

Step 11

6E–112

3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0123 – TP Sensor Circuit High Voltage

  (Cont'd)

Step

No

Yes

Value(s)

Action

10

1. Ignition “OFF.”
2. Disconnect the ECM, and check for an open sensor

ground circuit to the TP sensor.

3. If a problem is found, repair it as necessary.

Was the sensor ground circuit to the TP sensor open?

—

Verify repair

Go to 

Step 12

11

Replace the TP sensor.

Is the action complete?

—

Verify repair

—

12

Replace the ECM.

Is the action complete?

—

Verify repair

—