Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1275

6E1–176

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0140 – O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)

  (Cont'd)

Step

No

Yes

Value(s)

Action

7

1. Reconnect the PCM harness.
2. Ignition ON.
3. With the Bank 1 HO2S 2 sensor harness

disconnected, use a Digital Voltmeter (DVM) to
measure the voltage between the HO2S heater
ground wire and each signal circuit wire.

Does each signal circuit measure in the specified
range?

3–4 V

Go to Step 9 

Go to Step 8 

8

Check for a short to ground or voltage in both signal
circuits.

Was a problem found?

—

Verify repair

Go to Step 11

9

1. Jumper the high and low signal wires to the heater

ground wire.

2. Ignition ON.

Using a Tech 2, is the Bank 1 HO2S 2 voltage in the
specified range?

0–10 mV

Go to Step 10

Go to Step 11

10

Replace Bank 1 HO2S 2.

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

—

6E1–177

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0141 O2 SENSOR HEATER CIRCUIT

MALFUNCTION (BANK 1 SENSOR 2)

060R100031

Circuit Description

Heated oxygen sensors are used to minimize the amount
of time required for ”Closed Loop” fuel control operation
and to allow accurate catalyst monitoring. The oxygen
sensor heater greatly decreases the amount of time
required for fuel control sensors Bank 1 HO2S 1 and Bank
2 HO2S 1 to become active. Oxygen sensor heaters are
required by catalyst monitor sensors Bank 1 HO2S 2 and
Bank 2 HO2S 2 to maintain a sufficiently high
temperature which allows accurate exhaust oxygen
content readings further from the engine.
The powertrain control module (PCM) will run the heater
test only after a cold start (determined by engine coolant
and intake air temperature at the time of start–up) and
only once during an ignition cycle. When the engine is
started the PCM will monitor the HO2S voltage. When the
Bank HO2S voltage indicates a sufficiently active sensor,
the PCM looks at how much time has elapsed since
start–up. If the PCM determines that too much time was
required for the Bank 1 HO2S 2 to become active, a
Diagnostic Trouble Code P0141 will set.  DTC P0141 is a
type B code.

Conditions for Setting the DTC

D

No related Diagnostic Trouble Codes.

D

Intake air temperature (IAT) is less than 32

°

C (90

°

F)

at start–up.

D

Engine coolant temperature (ECT) is less than 32

°

C

(90

°

F) at start–up.

D

IAT and ECT are within 6.75

°

C (44

°

F) of each other at

start–up.

D

Ignition voltage is between 11 volts and 16.6 volts.

D

Throttle angle is less than 40%.

D

Average calculated airflow is less than 26 g/second
during the sample period.

D

Bank 1 HO2S 2 voltage does not change more than
148 mV from the bias voltage (between 400 mV–500
mV) for a longer amount of time than it should. The
maximum amount of time to come up to operating
range is 375 seconds. This warm–up time depends on
the engine coolant temperature at start–up and intake
air temperature at start–up.

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.

Conditions for Clearing the MIL/DTC

D

The PCM will turn the MIL OFF on the third consecutive
trip cycle duringwhich the diagnostic has been run and
the fault condition is no longer present.

6E1–178

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

D

A history Diagnostic Trouble Code P0141 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

D

Diagnostic Trouble Code P0141 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 circuits. If the harness appears to be OK,
observe the 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.

Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart:
 2.The HO2S should be allowed to cool before

performing this test. If the HO2S heater is
functioning, the signal voltage will gradually increase
or decrease as the sensor element warms. If the
heater is not functioning, the HO2S signal will
remain near the 450 mV bias voltage.

 4.This ensures that the ignition feed circuit to the

HO2S is not open or shorted. The test light should
be connected to a good chassis ground, in case the
HO2S low or HO2S heater ground circuit is faulty.

 5.This checks the HO2S heater ground circuit.

6.This checks for an open or shorted HO2S heater

element.

11. An open HO2S signal or low circuit can cause the

HO2S heater to appear faulty. Check these circuits
before replacing the sensor.

DTC P0141 – O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2) 

 

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

NOTE: If the engine has just been operating, allow the
engine to cool for about one half hour before
proceeding.

1. Ignition OFF, engine OFF.
2. Install the Tech 2.
3. Ignition ON, engine OFF monitor the Bank 1 HO2S

2 voltage.

Does the HO2S voltage go from bias voltage to above
or below the specified values?

Above 650

mV or below

250 mV

Refer to

Diagnostic

Aids 

Go to Step 3 

3

Inspect the fuse for Bank 1 HO2S 2 ignition feed.

Is the fuse open?

—

Go to Step 15

Go to Step 4 

4

1. Ignition OFF.
2. Raise the vehicle.
3. Disconnect the Bank 1 HO2S 2 electrical connector.
4. Using a test light connected to a good ground (do

not use Bank 1 HO2S 2 heater ground or Bank 1
HO2S 2 low), probe the ignition feed circuit at the
Bank 1 HO2S 2 electrical connector (PCM harness
side).

Does the test light illuminate?

—

Go to Step 5 

Go to Step 7 

5

Connect the test light between the Bank 1 HO2S 2
ignition feed and the Bank 1 HO2S 2 heater ground.

Does the test light illuminate?

—

Go to Step 6 

Go to Step 8 

6E1–179

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0141 – O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2) 

  (Cont'd)

Step

No

Yes

Value(s)

Action

6

1. Allow the HO2S to cool for at least 10 minutes.
2. Using a Digital Voltmeter (DVM), measure the

resistance between the Bank 1 HO2S 2 ignition
feed and the Bank 1 HO2S 2 heater ground at the
Bank 1 HO2S 2 pigtail.

Is the HO2S resistance within the specified values?

3–6 

W

Go to Step 9 

Go to Step 10

7

Repair the open Bank 1 HO2S 2 ignition feed circuit to
Bank 1 HO2S 2.

Is the action complete?

—

Verify repair

—

8

Repair the open Bank 1 HO2S 2 heater ground circuit.

Is the action complete?

—

Verify repair

—

9

1. Check for a poor connection at the Bank 1 HO2S 2

harness terminals.

2. If a poor connection is found, replace the terminals.

Was a poor connection found?

—

Verify repair

Go to Step 10

10

1. Ignition OFF.
2. Disconnect the PCM and check the continuity of the

Bank 1 HO2S 2 signal circuit and the Bank 1 HO2S
2 low circuit.

3. If the Bank 1 HO2S 2 signal circuit or the HO2S low

circuit measures over 5 

W

, repair the open or poor

connection as necessary.

Was a problem found?

—

Verify repair

Go to Step 11

11

Check for a poor Bank 1 HO2S 2 high or low circuit
terminal connection at the Bank 1 HO2S 2 harness
connector and replace the terminal(s) if necessary.

Did any terminals require replacement?

—

Verify repair

Go to Step 12

12

Check for a poor Bank 1 HO2S 2 low circuit terminal
connection at the PCM and replace the terminal if
necessary.

Did the terminal require replacement?

—

Verify repair

Go to Step 13

13

Check for a poor Bank 1 HO2S 2 high circuit terminal
connection at the PCM and replace the terminal if
necessary.

Did the terminal require replacement?

—

Verify repair

Go to Step 14

14

Replace Bank 1 HO2S 2.

Is the action complete?

—

Verify repair

—

15

Locate and repair the short to ground in Bank 1 HO2S 2
ignition feed circuit and replace the faulty fuse.

Is the action complete?

—

Verify repair

—