DTC P0133 HO2S Slow Response Sensor 1. Pontiac Bonneville 2000

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2000 🢒 Bonneville 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P0133 HO2S Slow Response Sensor 1

Engine Controls Components
Heated Oxygen Sensors
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice

Circuit Description

The powertrain control module (PCM) continuously monitors the heated oxygen sensor (HO2S) activity for 120 seconds. During the monitoring period the PCM counts the number of times that the a rich to lean and lean to rich response is indicated and adds the amount of time it took to complete all transitions. With this information, an average time for each transition can be determined. If the average response time 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 malfunctioning and should be replaced.

Conditions for Running the DTC

•	None of the following active DTCs are present:

-	Throttle position (TP) sensor

-	Evaporative emissions (EVAP) system

Misfire

-	Intake air temperature (IAT) sensor

-	Manifold absolute pressure (MAP) sensor

Fuel trim

-	Fuel injector circuit

-	EGR pintle position

-	Engine coolant temperature (ECT) sensor

-	Crankshaft position (CKP) sensor

-	Mass air flow (MAF) sensor

•	The engine has been running in closed loop fuel control for at least 60 seconds.

•	The engine speed is between 1000 RPM and 3000 RPM.

•	The engine coolant temperature is more than 50°C (122°F).

•	The mass air flow is between 10 g/s and 30 g/s.

Conditions for Setting the DTC

VIN K--HO2S 1 lean to rich average transition response time during the sample period was more than 140 milliseconds or rich to lean average transition response time during the sample period was more than 107 milliseconds.

VIN 1--HO2S 1 lean to rich average transition response time during the sample period was more than 130 milliseconds or rich to lean average transition response time during the sample period was more than 110 milliseconds.

Action Taken When the DTC Sets

•	The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.

•	The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

Conditions for Clearing the MIL/DTC

•	The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed.

•	The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

•	The DTC can be cleared by using a scan tool.

Diagnostic Aids

Check for the following conditions:

•	Faulty connections at PCM--Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. Use a corresponding mating terminal to test for proper terminal tension.

•

Inspect the wiring harness for damage. If the harness appears to be OK, observe the HO2S 1 display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the malfunction. If DTC P0133 cannot be duplicated, Reviewing the Fail 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

The numbers below refer to the step numbers on the diagnostic table.

When the system is operating correctly the HO2S voltage should toggle to more than and less than the specified values.

If the low circuit is shorted to ground the HO2S voltage will be less than 400 mV when the signal circuit is jumped to ground.

The specified value is what is measured on a correctly operating system.

This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read-only memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.

Step

Action

Values

Yes

Did you perform the Powertrain On Board Diagnostic (OBD) System Check?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Important: If any other DTCs are set (except HO2S DTCs), refer to the other DTCs before proceeding with this table.

Ensure the engine is at operating temperature.
Operate the engine at more than 1200 RPM for 2 minutes.
With a scan tool, observe the HO2S voltage parameter.

Is the HO2S voltage varying outside the specified range?

400-500 mV

Go to Step 3

Go to Step 4

Operate the vehicle within the Failure Records conditions.

Does the scan tool indicate this DTC failed this ignition?

Go to Step 4

Go to Diagnostic Aids

Inspect and test for the following:

•	An exhaust leak, refer to Exhaust Leakage - Not OBD II in Engine Exhaust.

•	Verify that the HO2S is installed correctly.

•	Any damaged wiring, refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 5

Turn ON the ignition.
Disconnect the HO2S.
Jumper the signal circuit (PCM side) to a good ground.
With a scan tool, observe the HO2S voltage parameter.

Is the HO2S voltage more than the specified value?

400 mV

Go to Step 6

Go to Step 10

Remove the jumper wire.
Measure the voltage on the HO2S signal circuit (PCM side) using a digital multimeter (DMM) connected to a good ground.

Does the voltage approximately equal the specified value?

4.5 V

Go to Step 7

Go to Step 9

Measure the voltage on the HO2S low circuit (PCM side) using the DMM connected to a good ground.

Does the voltage approximately equal the specified value?

5 V

Go to Step 11

Go to Step 8

Test the low circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 13

Test the signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 13

Test the low circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 14

Test for faulty connections at the HO2S. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 12

Important: Determine the cause of contamination before replacing the sensor.

Inspect and test for the following:

•	Fuel contamination, refer to Alcohol/Contaminants-in-Fuel Diagnosis .

•	Excessive engine oil or coolant consumption, refer to Oil Consumption Diagnosis in Engine Mechanical.

Notice: Contamination of the oxygen sensor can result from the use of an inappropriate RTV sealant (not oxygen sensor safe) or excessive engine coolant or oil consumption. Remove the HO2S and visually inspect the portion of the sensor exposed to the exhaust stream in order to check for contamination. If contaminated, the portion of the sensor exposed to the exhaust stream will have a white powdery coating. Silicon contamination causes a high but false HO2S signal voltage (rich exhaust indication). The control module will then reduce the amount of fuel delivered to the engine, causing a severe driveability problem. Eliminate the source of contamination before replacing the oxygen sensor.