Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Service manual - part 1265

6E1–136

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0118 ENGINE COOLANT 

TEMPERATURE (ECT) SENSOR CIRCUIT HIGH INPUT

060R100028

Circuit Description

The engine coolant temperature (ECT) sensor is a
thermistor mounted in the engine coolant stream. The
powertrain control module (PCM) applies a voltage
(about 5 volts) through a pull–up resistor to the ECT signal
circuit. When the engine coolant is cold, the sensor
(thermistor) resistance is high, therefore the PCM will
measure a high signal voltage. As the engine coolant
warms, the sensor resistance becomes less, and the
ECT signal voltage measured at the PCM drops. With a
fully warmed up engine, the ECT signal voltage should
measure about 1.5 to 2.0 volts.  If the PCM detect a
continuous open in the ECT sensor or circuit, then a code
P0118 will set.  DTC P0118 is a type A code.

Conditions for Setting the DTC

D

Engine running time is longer than 180 seconds.

D

The ECT sensor signal indicates an engine coolant
temperature of –39

°

C (–38

°

F) or less (about 5 volts)

for a total of 12.5 seconds over a 25–second period.

The above conditions are met for 100 test failures within a
200 test sample(125 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 substitute the ECT reading with a default
engine coolant temperature value. The default value is

based on start–up intake air temperature and running
time.

D

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

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 P0118 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

D

Diagnostic Trouble Code P0118 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

Damaged harness – Inspect the wiring harness for
damage, shorts to ground, shorts to battery positive,
and open circuit. If the harness appears to be OK,
observe the ECT display on the Tech 2 while moving
connectors and wiring harnesses related to the ECT
sensor. A change in the ECT display will indicate the
location of the fault.

6E1–137

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

If Diagnostic Trouble Code P0118 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 DTC P1115 Diagnostic Chart may isolate
the cause of the fault.

Test Description

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

3.If Diagnostic Trouble Code P0118 can be repeated

only by duplicating the Failure Records condition,
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.

Intake Air Temperature Sensor

°

C

°

F

OHMS

Temperature vs. Resistance Values (approximate)

100

212

177

80

176

332

60

140

667

45

113

1188

35

95

1802

25

77

2796

15

59

4450

5

41

7280

–5

23

12300

–15

5

21450

–30

–22

52700

–40

–40

100700

DTC P0118 – ECT 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. Observe the ”Eng Cool Temp” display on the Tech 2.

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

–39

°

C

(–38

°

F)

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 ”DTC” info for

Diagnostic Trouble Code P0118.

Does the Tech 2 indicate Diagnostic Trouble Code
P0118 failed?

—

Refer to Test

Description 

Refer to

Diagnostic

Aids 

4

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 or above the specified value?

140

°

C

(284

°

F)

Go to Step  6 

Go to Step  5 

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 or above the specified value?

140

°

C

(284

°

F)

Go to Step  7 

Go to Step  8 

6

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

Did any terminals require replacement?

—

Verify repair

Go to Step

10 

6E1–138

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0118 – ECT Sensor Circuit High Input 

  (Cont'd)

Step

No

Yes

Value(s)

Action

7

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 

8

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 

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 

10

Replace the ECT sensor.

Is the action complete?

—

Verify repair

—

11

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

—

6E1–139

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

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

SENSOR CIRCUIT RANGE/PERFORMANCE PROBLEM 

060R100029

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

D

The Engine is running.

D

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

D

IAC is between 10 and 160 counts.

D

ECT is above –10

°

C (14

°

F).

D

The MAP value changes by less than 2 kPa.

The above conditions are met for 100 test failures within a
200 test sample (125 msec/test)
Stuck High–

D

MAP value is below 55 kPa.

D

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

Stuck Low–

D

MAP value is below 50 kPa.

D

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

D

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

D

The PCM will store conditions which were present
when the Diagnostic Trouble Code 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 P0121 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

D

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