Isuzu Rodeo UE. Manual - part 348

6E2–147

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Verifies that the fault is present.

3. If DTC P0118 can be repeated only by duplicating

the Failure Records conditions, refer to the
“Temperature vs. Resistance Value” table. The
table may be used to test the ECT sensor at various
temperatures to evaluate the possibility of a
“shifted” sensor that may be shorted above or below
a certain temperature. If this is the case, replace
the ECT sensor. If the ECT sensor appears to be
OK, the fault is intermittent; refer to

Diagnostic Aids.

Engine Coolant Temperature Sensor

OHMS

Temperature

vs. Resistance

Values

(approximate)

100

212

177

176

332

140

667

113

1188

1802

2796

4450

7280

–5

12300

–15

21450

–30

–22

52700

–40

100700

DTC P0118 – ECT Sensor Circuit High Voltage

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. Observe the “Eng Cool Temp” display on the Tech 2.

Is the “Eng Cool Temp” below the specified value?

–39

(–38

Go to

Step 4

Go to

Step 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 “DTC” info for DTC

P0118.

Does the Tech 2 indicate DTC P0118 failed?

—

Refer to

Test

Description

Refer to

Diagnostic

Aids

1. Disconnect the ECT sensor electrical connector.
2. Jumper the ECT signal circuit and the sensor

ground circuit together at the ECT sensor harness
connector.

3. Observe the “Eng Cool Temp” display on the Tech 2.

Is the “Eng Cool Temp” at the specified value?

140

(284

Go to

Step 6

Go to

Step 5

1. Jumper the ECT signal circuit at the ECT sensor

harness connector to chassis ground.

2. Observe the “Eng Cool Temp” display on the Tech 2.

Is the “Eng Cool Temp” at the specified value?

140

(284

Go to

Step 7

Go to

Step 8

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

Did any terminals require replacement?

—

Verify repair

Go to

Step 10

6E2–148

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0118 – ECT Sensor Circuit High Voltage

(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 11

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

—

6E2–149

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0121 TP System Performance

D06RW059

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 powertrain control module (PCM) for fuel control and
many of the PCM-controlled outputs. The PCM monitors
throttle position and compares actual throttle position
from the TP sensor to a predicted TP value calculated
from engine speed. If the PCM detects an out-of-range
condition, DTC P0121 will set.

Conditions for Setting the DTC

The engine is running.

No MAP DTCs, or P0121, P0122, P1122, P0123 DTCs
are set.

MAP reading is below 55 kPa.

Throttle is steady, throttle angle is changing less than
1%.

Predicted throttle angle is not close to actual throttle
angle.

Above conditions are present for a total of 12.5
seconds over a 25-second period of time.

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 DTC was set as Freeze Frame and in the
Failure Records data.

The PCM will use a default throttle position based on
mass air flow 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 DTC P0121 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0121 can be cleared by using the Tech 2 “Clear
info ” function or by disconnecting the PCM battery
feed.

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 EGR
Valve.

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

The TP Sensor share a ground with the EGR Valve and
the IAT Sensor.

6E2–150

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

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. If the harness appears to be OK, observe the
ECT 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 and DTC P1121 Diagnostic
Charts may isolate the cause of the fault.

DTC P0121 –TP System Performance

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 not running.
2. Observe the MAP reading on the Tech 2.

Is the MAP reading less than the specified value?

65 kPa

Go to

Step 3

Go to

Step 6

1. Disconnected the MAP sensor.
2. Connect a test light between the 5 volt reference “A”

circuit and the MAP signal circuit at the MAP sensor
harness connector.

3. Observe the MAP reading on the Tech 2.

Is the MAP reading less than the specified value? (If no,
start with diagnosis chart for other sensors in the circuit
and see if 5V returns.)

65 kPa

Go to

Step 5

Go to

Step 4

1. Check the MAP signal circuit between the PCM and

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

2. If the MAP signal circuit is open or shorted, repair it

as necessary.

Was the MAP signal circuit open or shorted?

—

Verify repair

Go to

Step 12

Replace the MAP sensor.

Is the action complete?

—

Verify repair

—

Observe the TP angle reading on the Tech 2 while
slowly opening the throttle.

Does the TP angle increase steadily and evenly from
the closed throttle value to the wide open throttle
value?

Closed

throttle = 0%

Wide open

throttle =

100%

Refer to

Diagnostic

Aids

Go to

Step 7

1. Disconnect the TP sensor.
2. Observe the TP sensor reading on the Tech 2.

Is the TP sensor reading near the specified value?

0 V

Go to

Step 8

Go to

Step 9

1. Connect a test light between the 5 volt reference “A”

circuit and the TP sensor signal circuit at the TP
sensor harness connector.

2. Observe the TP sensor reading on the Tech 2.

Is the TP sensor reading at the specified value?

5 V

Go to

Step 11

Go to

Step 10

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