Isuzu Rodeo UE. Manual - part 191

6E1–135

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0122 THROTTLE POSITION (TP) SEN-

SOR CIRCUITLOW INPUT 

D06RX045

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 below 1 volt at closed throttle
to about 4 volts at wide open throttle(WOT).
The TP signal is used by the powertrain control module
(PCM) for fuel control and most of the PCM–controlled
outputs.  If the PCM detect a continuous short to ground
in the TP sensor or circuit, then a code P0122 will set.
Diagnostic Trouble Code P0122 is type A code.

Conditions for Setting the DTC

f

The ignition is ON.

f

Throttle Position sensor signal voltage is less than 0.22
volt for a total of 0.78 second over a 1.5–second period.

Action Taken When the DTC Sets

f

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

f

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

f

The PCM will use a default throttle position based on
MAP and RPM.

Conditions for Clearing the MIL/DTC

f

The PCM 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.

f

A history Diagnostic Trouble Code P0122 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

f

Diagnostic Trouble Code P0122 can be cleared by
using the Scan Tool’s ”Clear Info” function.

Diagnostic Aids

f

Poor connection at PCM – Inspect harness connectors
for backed–out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal–to–wire connection.

f

The TP sensor shares a 5 Volt reference with the MAP
sensor and Fuel Pressure sensor.

If these codes are also set, it could indicate a
problem with the 5 Volt reference circuit or
components itself.

f

The TP sensor share a ground with the MAP and the
Fuel Pressure sensor.

f

Damaged harness – Inspect the wiring harness for
damage, shorts to ground, shorts to battery positive,
and open circuits. If the harness appears to be OK,
observe the throttle position 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.  

6E1–136

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

If Diagnostic Trouble Code P0122 cannot be duplicated,
the information included in the Failure Records data can
be useful in determining vehicle mileage since the
Diagnostic Trouble Code was last set. If it is determined

that the Diagnostic Trouble Code occurs intermittently,
performing the Diagnostic Trouble Code P1122
Diagnostic Chart may isolate the cause of the fault.

DTC P0122 – TP Sensor Circuit Low Input 

 

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 ”Throttle

Position Sensor” display on the Tech 2.

Is the ”Throttle Position Sensor” below the specified
value?

0.22 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 the “Diagnostic Trouble

Code” info for Diagnostic Trouble Code P0122.

Does the Tech 2 indicate DTC P0122 failed?

—

Go to Step  4 

Refer to

Diagnostic

Aids 

4

1. Ignition OFF.
2. Disconnect the TP sensor electrical connector.
3. Jumper the 5 volt reference circuit and the  Throttle

Position signal together at the Throttle Position
sensor harness connector.

4. Ignition ON.
Observe the ”Throtle Position Sensor” display on the
Tech 2.

Is the ”Throttle Position Sensor” at the specified value?

5 V

Go to Step

10 

Go to Step  5 

5

1. Disconnect jumper.
2. Connect a test light between B+ and the Throttle

Position sensor signal circuit at the Throttle Position
sensor harness connector.

Observe the ”Throttle Position Sensor” display on the
Tech 2.

Is the ”Throttle Position Sensor” at the specified value?
(if no, start with the diagnosis chart for other sensors in
the circuit and see if 5V returns.)

5 V

Go to Step  6 

Go to Step  8 

6

1. Ignition OFF.
2. Disconnect the PCM and check the 5 volt reference

circuit for an open or short to ground.

3. If the 5 volt reference circuit is open or shorted to

ground, repair it as necessary.

Was the 5 volt reference circuit open or shorted to
ground?

—

Verify repair

Go to Step  7 

7

Check the 5 volt reference circuit for a poor connection
at the PCM and replace the terminal if necessary.

Did the terminal require replacement?

—

Verify repair

Go to Step

12 

6E1–137

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0122 – TP Sensor Circuit Low Input 

  (Cont'd)

Step

No

Yes

Value(s)

Action

8

1. Ignition OFF.
2. Disconnect the PCM, and check the TP signal

circuit for an open, short to ground, or short to the
sensor ground circuit.

3. If the TP sensor signal circuit is open or shorted to

ground, repair it as necessary.

Was the TP signal circuit open or shorted to ground?

—

Verify repair

Go to Step  9 

9

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

Did the terminal require replacement?

—

Verify repair

Go to Step

12 

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 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

—

6E1–138

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0123 THROTTLE POSITION (TP) SEN-

SOR CIRCUIT HIGH INPUT

D06RX045

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 below 1 volt at closed throttle
to about 4 volts at wide open throttle (WOT).
The TP signal is used by the powertrain control module
(PCM) for fuel control and most of the PCM–controlled
outputs.  If the PCM detect a continuous open in the TP
sensor or circuit, then a code P0123 will set.  DTC P0123
is a type A code.

Conditions for Setting the DTC

f

The ignition is ON.

f

Throttle Position sensor signal voltage is greater than
4.78 volts for a total of 0.78 second over a 1.5–second
period.

Action Taken When the DTC Sets

f

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

f

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

f

The PCM will use a default throttle position based on
MAP and RPM.

Conditions for Clearing the MIL/DTC

f

The PCM 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.

f

A history Diagnostic Trouble Code P0123 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

f

Diagnostic Trouble Code P0123 can be cleared by
using the Scan Tool’s ”Clear Info” function.

Diagnostic Aids

Check for the following conditions:

f

Poor connection at PCM – Inspect harness connectors
for backed–out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal–to–wire connection.

f

The TP sensor shares a 5 Volt reference with the MAP
sensor and Fuel Pressure sensor.

If these codes are also set, it could indicate a
problem with the 5 Volt reference circuit or
components itself.

f

The TP sensor share a ground with the MAP and the
Fuel Pressure sensor.

f

Damaged harness – Inspect the wiring harness for
damage, shorts to ground, shorts to battery positive
and open circuits. 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.