Content .. 188 189 190 191 ..

Isuzu Rodeo UE. Manual - part 190

6E1–131

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P118 – ECT Sensor Circuit High Input

(Cont'd)

Step

Yes

Value(s)

Action

1. Ignition OFF.
2. Disconnect the PCM, and check the ECT sensor

ground circuit for an open.

3. If the ECT sensor ground circuit is open, repair it as

necessary.

Was the ECT sensor ground circuit open?

—

Verify repair

Go to Step 9

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

circuit for an open.

3. If the ECT sensor signal circuit is open, repair it as

necessary.

Was the ECT signal circuit open?

—

Verify repair

Go to Step 9

Check for a poor sensor ground or ECT signal circuit
terminal connection at the PCM and replace
terminal(s) if necessary.

Did any of the terminals need to be replaced?

—

Verify repair

Go to Step

Replace the ECT sensor.

Is the action complete?

—

Verify repair

—

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

—

6E1–132

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0121 THROTTLE POSITION (TP) SEN-

SOR CIRCUIT RANGE/PERFORMANCE PROBLEM

D06RX045

Circuit Description

The throttle position (Throttle Position) sensor circuit
provides a voltage signal that changes relative to throttle
blade angle. The signal voltage will vary from about 0.25
volts at closed throttle to about 4.75 volts at wide open
throttle (WOT).
The Throttle Position (TP) signal is used by the
powertrain control module (PCM) for fuel control and
most of the PCM–controlled outputs. The PCM monitors
throttle position and compares actual throttle positions
from the TP sensor to a predicted TP value calculated
from engine speed. If the PCM detects an out–of–range
condition, then a DTC code P0121 will set. DTC P0121 is
type A code.

Conditions for Setting the DTC

The Engine is running.

No MAP, ECT, TP, CKP, EGR, EVAP or DTC’s are set.

IAC is between 10 and 160 counts.

ECT is above –10

C (14

F).

The MAP value changes by less than 2 kPa.

All the above mentioned conditions are met, and one of
the following conditions occurs for a total of 12.5 seconds
over a 25–second period of time.
Stuck High–

MAP value is below 55 kPa.

Actual TP value is greater than the PCM’s estimated
TP value (Estimated TP value is based on MAP and
RPM).

Stuck Low–

MAP value is below 50 kPa.

Actual TP value is less than the PCM’s estimated TP
value (Estimated TP value is based on MAP and
RPM).

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

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

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

Conditions for Clearing the MIL/DTC

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.

A history Diagnostic Trouble Code P0121 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

DTC P0121 can be cleared by using the Scan Tool’s
”Clear Info” function.

6E1–133

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Diagnostic Aids

Check for the following conditions:

Skewed MAP signal or faulty MAP sensor – An
incorrect MAP signal may cause the PCM to incorrectly
calculate the predicted TP sensor value during high
engine load situations. Check for an unusually low
MAP reading. This condition can cause DTC P0121 to
be set.

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.

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

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.

Damaged harness – Inspect the wiring harness for
damage; an open circuit, a short to ground, or a short
to voltage. If the harness appears to be OK, observe
the MAP display on the Tech 2 while moving
connectors and wiring harnesses related to the sensor.
A change in the display will indicate the location of the
fault.

If DTC P0121 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set. If
it is determined that the DTC occurs intermittently,
performing the DTC P1122 or P1121 Diagnostic Chart
may isolate the cause of the fault.

DTC P0121 TP Sensor/Range Performance Problem

Step

Action

Value(s)

Yes

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

—

Go to Step 2

Go to OBD

System

Check

1. Ignition ON engine OFF
2. Review and record Tech 2 Failure Records data,

then clear the DTC’s.

3. Operate the vehicle within Failure Records

conditions as noted.

4. Using a Tech 2, monitor ”DTC” info for DTC P0121.

Does the Tech 2 indicate that DTC P0121 ”Ran and
Passed?”

—

Refer to

Diagnostic

Aids

Go to Step 3

1. Ignition ON, engine OFF.
2. Monitor the TP value on the Tech 2 while moving the

throttle between 0% and 100%.

Does the TP value on the Tech 2 move smoothly from
0% (0.25 volts) to 100% (4.75 volts)? (if no, start with
the diagnosis chart for other sensors in the circuit and
see if 5V returns.)

—

Go to Step 4

Go to Step 11

1. Ignition OFF.
2. Disconnect the Throttle Position (TP) Sensor

electrical connector, located on the RH side of the
Throttle body.

3. Start the vehicle, and monitor the TP value with the

Tech 2.

Does the TP value on the Tech 2 hold steadily within the
given range?

0–0.25 volts

Go to Step 6

Go to Step 5

Check the TP sensor signal circuit; between the TP
sensor and the Powertrain Control Module (PCM), for a
short to voltage.

Was the problem found?

—

Verify repair

Go to Step 12

Check the TP sensor circuit, between the TP sensor
and the PCM, the following conditions:

A short to ground

An open circuit

Was the problem found?

—

Verify repair

Go to Step 7

6E1–134

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0121 TP Sensor/Range Performance Problem

(Cont'd)

Step

Yes

Value(s)

Action

Check the 5 volt signal circuit, between the TP sensor
and the PCM, for the following conditions:

An open circuit

A short to ground

A short to voltage

Was the problem found?

—

Verify repair

Go to Step 8

1. Ignition OFF.
2. Place a fused jumper between the TP sensor circuit

and the 5 volt signal circuit both at the wiring
harness’ TP sensor connector.

3. Ignition ON, Engine OFF.
4. Observe the TP value displayed on the Tech 2?

Does the Tech 2 read the following value?

about 5 volts

100%

Go to Step 9

Go to Step 12

Check the TP sensor ground circuit, between the TP
sensor and the PCM, for the following conditions:

An open circuit

A short to ground

A short to voltage

Was the problem found?

—

Verify repair

Go to Step 10

1. Ignition OFF.
2. Place a Digital Multimeter (DVM), set to measure

voltage, between the ground circuit and the 5 volt
signal circuit, both at the wiring harness’ TP sensor
connector.

3. Ignition ON, Engine OFF.

Does the DVM read the following value?

about 5 volts

Go to Step 11

Go to Step 12

Replace the TP sensor.
Verify repair.

—

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.

Verify repair.

—

Content .. 188 189 190 191 ..