Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1267

6E1–144

RODEO Y22SE 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

—

6E1–145

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) 

P0123 THROTTLE POSITION (TP) SENSOR CIRCUIT HIGH INPUT

060R100029

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

D

The ignition is ON.

D

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

The above conditions met for 100 test failures within a 200
test samples (7.81 msec/test).

Action Taken When the DTC Sets

D

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

D

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

D

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

Conditions for Clearing the MIL/DTC

D

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.

D

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

D

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

Diagnostic Aids

Check for the following conditions:

D

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.

D

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.

D

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

D

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

6E1–146

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

related to the TP sensor. A change in the display will
indicate the location of the fault.

D

Faulty Throttle Position 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 Diagnostic Trouble Code P0123 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 theDiagnostic Trouble Code P1121
Diagnostic Chart may isolate the cause of the fault.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart:
7. Components that share the TP sensor 5 volt

reference circuit include the following devices:

D

EGR valve

D

Fuel Tank Pressure sensor

D

MAP sensor

Disconnect the component while observing the
Throttle Position sensor display on the Tech 2. If the
reading changes drastically when this component is
disconnected, replace the component that affected
the reading.

DTC P0123 – TP Sensor Circuit High 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” above the specified
value?

4.78 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 “Diagnostic Trouble Code”

info for Diagnostic Trouble Code P0123.

Does the Tech 2 indicate Diagnostic Trouble Code
P0123 failed.

—

Go to Step  4 

Refer to

Diagnostic

Aids 

4

1. Disconnect the Throttle Position sensor electrical

connector.

2. Observe the ”Throttle Position Sensor” display on

the Tech 2.

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

0 V

Go to Step  5 

Go to Step  6 

5

Probe the sensor ground circuit at the Throttle Position
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 PCM.
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 

6E1–147

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0123 – TP Sensor Circuit High Input

  (Cont'd)

Step

No

Yes

Value(s)

Action

7

1. Ignition ON.
2. Monitor the ”Throttle Position Sensor” Tech 2

display while disconnecting each of the
components that share the 5 volt reference circuit
(one at a time).

3. If the ”Throttle Position Sensor” Tech 2 display

changes, service the component(s) that caused the
display to change when disconnected.

Does disconnecting any of these components cause
the ”Throttle Position Sensor” display to change?

—

Verify repair

Go to Step  8 

8

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

circuit.

4. If the 5 volt reference circuit is shorted, repair it as

necessary.

Was the 5 volt reference circuit shorted?

—

Verify repair

Go to Step  9 

9

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

Did any terminals require replacement?

—

Verify repair

Go to Step

11 

10

1. Ignition OFF.
2. Disconnect the PCM, and check for an open sensor

ground circuit to the Throttle Position sensor.

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

Was the sensor ground circuit to the Throttle Position
sensor open?

—

Verify repair

Go to Step

12 

11

Replace the Throttle Position 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

—