Isuzu Trooper (1998-2002 year). Manual - part 448

6E–162

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) 

P0133 HO2S Slow Response Bank 1 Sensor 1

D06R200013

Circuit Description

The powertrain control module (PCM) continuously
monitors the heated oxygen sensor (HO2S) activity for 90
seconds after “closed loop” has been enabled.  During the
monitoring period the PCM counts the number of times
that a rich-to-lean and lean-to-rich response is indicated
and adds the amount of time it took to complete all
rich-to-lean transitions and lean-to-rich transitions.  With
this information, an average time for rich-to-lean and
lean-to-rich transitions can be determined.  If the average
response time of either transition is too slow, a DTC
P0133 will be set.
A lean-to-rich transition is indicated when the HO2S
voltage changes from less than 300 mV to greater than
600 mV. A rich-to-lean transition is indicated when the
HO2S voltage changes from more than 600 mV to less
than 300 mV.  An HO2S that responds too slowly is likely
to be faulty and should be replaced.

Conditions for Setting the DTC

D

No related DTCs.

D

Engine coolant temperature (ETC) is above 60

°

C

(140

°

F).

D

Engine is operating in “closed loop”.

D

Engine has been running for at least 90 seconds.

D

Engine speed is between 1500 RPM and 3000 RPM.

D

Canister purge duty cycle is greater than 2%.

D

Mass air flow is between 18 g/second and 42 g/second.

D

All above conditions are met for 3 seconds.

D

90 seconds after “closed loop” has been enabled,
Bank1 HO2S 1 average transition time between
300 mV and 600 mV is too slow.  The lean-to-rich
average transition response time was longer than 94
milliseconds or rich-to-lean average transition
response time was longer than 105 milliseconds.

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

D

“Open loop” fuel control will be in effect.

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 DTC P0133 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D

DTC P0133 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

6E–163

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

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.  If the harness appears to be OK, observe the
Bank 1 HO2S 1 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 P0133 cannot be duplicated, 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. Verifies that the fault is currently present.

3. HO2S transition time, ratio mean volts and switching

DTCs set for multiple sensors indicate probable
contamination.  Before replacing the sensors,
isolate and correct the source of the contamination
to avoid damaging the replacement sensors.

6E–164

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

DTC P0133 – HO2S Slow Response Bank 1 Sensor 1

 

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 any DTCs are set (expect P0153, P1133,
P1134, P1153, and/or P1154), refer to those DTCs
before proceeding with this diagnostic chart.

1. Install the Tech 2.
2. Idle the engine at normal operating temperature.
3. Operate the vehicle within parameters specified

under “Conditions for Setting the DTC” included in
Diagnostic Support.

4. Using a Tech 2, monitor “DTC” info for DTC P0133

until the DTC P0133 test runs.

5. Note the test result.

Does the Tech 2 indicate DTC P0133 failed this
ignition?

—

Go to 

Step 3

Check the

Procedure

Refer to

Diagnostic

Aids

3

Did the Tech 2 also indicate DTC P0153, P1133,
P1134, P1153, and/or P1154 failed this ignition?

—

Go to 

Step 17

Go to 

Step 4

4

Check for leaks at the pipe joints.

Are the joints leaking?

—

Go to 

Step 5

Go to 

Step 6

5

Tighten the U–bolt nuts at the leaking joints.

Is the action complete?

—

Go to 

Step 2

—

6

Check for gaskets that are damaged or improperly
installed.

Are there damaged or misaligned gaskets?

—

Go to 

Step 7

Go to 

Step 8

7

1. Replace damaged gaskets.
2. Align the connections.
3. Tighten the connections.

Is the action complete?

—

Go to 

Step 2

—

8

Check for loose exhaust flange connections.

Are the flange connections loose?

—

Go to 

Step 9

Go to 

Step 10

9

Tighten the stud nuts or bolts to specifications.

Is the action complete?

—

Go to 

Step 2

—

10

Check for burned or corroded exhaust pipes.

Are the exhaust pipes burned or corroded?

—

Go to 

Step 11

Go to 

Step 12

11

Replace the exhaust pipes, as required.

Is the action complete?

—

Go to 

Step 2

—

12

Check for leaks at the exhaust manifold.

Are there leaks at the exhaust manifold?

—

Go to 

Step 13

Go to 

Step 14

13

Tighten the bolts to specifications to replace the
manifold if necessary.

Is the action complete?

—

Go to 

Step 2

—

6E–165

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0133 – HO2S Slow Response Bank 1 Sensor 1

  (Cont'd)

Step

No

Yes

Value(s)

Action

14

Visually/physically inspect the following items:

D

Ensure that the Bank 1 HO2S 1 is securely
installed.

D

Check for corrosion on terminals.

D

Check terminal tension (at Bank 1 HO2S 1 and at
the PCM).

D

Check for damaged wiring.

Was a problem found in any of the above areas?

—

Go to 

Step 18

Go to 

Step 15

15

1. Disconnect Bank 1 HO2S 1.
2. Ignition “ON”.
3. Using a DVM at the PCM side of the HO2S 1

connector, measure the voltage between the high
signal circuit and ground.  Also measure the voltage
between the low signal circuit and ground.

Are both voltages in the specified range?

3-4 V

Go to 

Step 16

Go to 

Step 19

16

1. With Bank 1 HO2S 1 disconnected, jumper the high

and low (PCM side) signal circuits to ground.

2. Ignition “ON”.
3. Using a Tech 2, monitor the Bank 1 HO2S 1 voltage.

Does the Tech 2 indicate less than 10 mV and
immediately return to about 450 mV when the jumper is
removed?

—

Go to 

Step 21

Go to 

Step 22

17

Replace the affected heated oxygen sensors.

NOTE: Before replacing sensors, the cause of the
contamination must be determined and corrected.

D

Fuel contamination.

D

Use of improper RTV sealant.

D

Engine oil/coolant consumption.

Is the action complete?

—

Verify repair

—

18

Repair condition as necessary.

Is the action complete?

—

Verify repair

—

19

Check for faulty PCM connections or terminal damage.

Is the action complete?

—

Verify repair

Go to 

Step 20

20

Repair open, short or grounded signal circuit.

Is the action complete?

—

Verify repair

—

21

Replace Bank 1 HO2S 1.

Is the action complete?

—

Verify repair

—

22

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

—