DTC P0133 O2S Slow Response Sensor 1. Chevrolet S10 Pickup

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1996 🢒 S10 Pickup - 2WD 🢒 Engine 🢒 Engine Controls - 2.2L 🢒 DTC P0133 O2S Slow Response Sensor 1

Handling ESD Sensitive Parts Notice
Engine Controls Components
Pre and Post Oxygen Sensors
OBD II Symbol Description Notice

Circuit Description

The PCM continuously monitors the Oxygen Sensor 1 (O2S 1) activity for 100 seconds. During the monitor period, the PCM counts the number of times that the O2S 1 switches from rich to lean and from lean to rich. Then adds the amount of time that the O2S 1 took to complete all the switches. With this information, an average time for all switches can be determined. Whenever the average time to switch is too slow, a DTC P0133 will set.

If the oxygen sensor pigtail, the connector, or the terminal are damaged, replace the entire oxygen sensor assembly. Do not attempt to repair the wiring, the connector, or the terminals. In order for the sensor to operate properly, it must have a clean air reference.The oxygen sensor wires provide the clean air reference. Any attempt to repair the wires, the connectors, or the terminals could result in the obstruction of the air reference. Repairs to the wires, the connectors, or the terminals could degrade the oxygen sensor performance. Refer to Oxygen Sensor Replacement .

Conditions For Setting The DTC

•	When one or more of the following DTCs are not set, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0300, P0301, P0302, P0303, P0304, P0506, P0507, P1406, P1441

•	The average O2S 1 response times are greater than 249 ms for rich to lean sweeps or 249 ms for lean to rich sweeps

•	The engine speed is between 1600 RPM and 2600 RPM

•	The TP angle is between 8% and 20%

•	The ratio of response times is greater than 3.3 or less than 0.4 (manual transmission)

•	The Evaporative Emissions Control system is commanded open for greater than 60 %

•	The Purge Learned Memory is greater than approximately 191

•	The ratio of response times is greater than 3.5 or less than 0.8 (automatic transmission)

Action Taken When the DTC Sets

•	The Malfunction Indicator Lamp (MIL) illuminates after 2 consecutive ignition cycles in which the diagnostic runs with the fault active.

•	The PCM records the operating conditions at the time the diagnostic fails. The Freeze Frame and Failure Records buffers stores this information.

•	A history DTC is stored.

•	The coolant fan turns on.

•	Thr vehicle operates in an Open Loop.

Conditions for Clearing the MIL/DTC

•	The malfunction indicator lamp (MIL) will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault.

•	A history DTC will clear after 40 consecutive warm up cycles without a fault.

•	Use a scan tool to clear the DTCs.

Diagnostic Aids

DTC P0133 or slow response is most likely caused by one of the following:

•	The fuel pressure - The system will go rich if the fuel pressure is to high. The PCM can compensate for some increase, if the fuel pressure gets too high, a DTC P0133 may set. Refer to Fuel System Pressure Test .

•	A leaking fuel injector - A leaking or faulty fuel injector can cause the system to go rich.

•

The MAP sensor - An output that causes the PCM to sense a higher than normal manifold pressure (low vacuum) can cause the system to go rich. Disconnecting the MAP sensor will allow the PCM to set a fixed value for the MAP sensor. Substitute a different MAP sensor if the rich condition is gone while the sensor is disconnected.

•	The pressure regulator - Check for a leaking fuel pressure regulator diaphragm by checking for the presence of liquid fuel in the vacuum line to the regulator.

•	The TP sensor - An intermittent TP sensor output will cause the system to go rich due to a false indication of the engine accelerating.

•

The O2S 1 contamination - Inspect the O2S 1 for silicone contamination from fuel or use of improper RTV sealant. The sensor may have a white powdery coating and result in a high but false voltage signal (rich exhaust indication). The PCM will then reduce the amount of fuel delivered to the engine causing a severe surge or driveability problem.

Test Description

The numbers listed below refer to the step numbers in the diagnostic table.

The Powertrain OBD System Check prompts the Technician to complete some basic checks and store the Freeze Frame Data and the Failure records on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The technician can refer to this information on the scan tool later.

Before replacing the PCM, check terminals for improper mating, broken locks, or physical damage to the wiring harness. Reprogram the replacement PCM. Refer to the latest Techline information for programming procedures.

If the technician has not found any faults or any additional set DTCs, refer to the Diagnostic Aids for additional checks and information.

Step

Action

Value(s)

Yes

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Are any component DTCs set?

Go to the Applicable DTC Table

Go to Step 3

Install a scan tool.
Allow the engine to run at the operating temperature.
Operate the vehicle within the parameters specified under Conditions for Setting the DTC.
Using a scan tool, monitor the Lean/Rich Avg. (ms), Rich/Lean Avg. (ms), and Rich/Lean to Lean/Rich Ratio Sen. 1 (Greater than, Less than).

Do the parameters show averages less than the specified values or ratios greater than the specified values?

249 ms

3.5, 0.44

Go to Step 4

Go to Step 18

Visually/physically inspect the following items:

•	Check for a securely installed O2S 1

•	Check for corrosion on terminals.

•	Check for terminal tension (At O2S 1 and at the PCM).

•	Check O2S 1 ground circuit for a good connection.

•	Check for damaged wiring.

Was a problem found in any of the above areas?

Go to Step 9

Go to Step 5

Check the exhaust manifold for an exhaust leak near the engine.
Repair as necessary.

Was an exhaust leak found?

Go to Step 3

Go to Step 6

Turn the ignition OFF.
Disconnect the O2S 1 electrical connector at the sensor.
Using a scan tool, monitor the O2S 1 voltage.

Does the scan tool voltage indicate voltage within specified values?

407-509 mV

Go to Step 7

Go to Step 10

Jumper the O2S 1 high circuit (PCM side) signal circuit to a ground.
Using the scan tool, monitor the O2S 1 voltage.

Does the scan tool voltage indicate voltage below the specified value?

200 mV

Go to Step 8

Go to Step 11

Notice: Correct the source of the oxygen sensor contamination before replacing the sensor in order to prevent future contamination. Typical contamination sources include the following:

•	Fuel contamination

•	Use of improper RTV sealant

•	Engine oil or engine coolant consumption

Replace the Oxygen Sensor. Refer to Oxygen Sensor Replacement .

Is the action complete?

Go to Step 17

Repair the condition as necessary.

Is the action complete?

Go to Step 17

Repair the short to ground in the O2S 1 signal circuit. Refer to Wiring Repairs .

Is the action complete?

Go to Step 17

Remove the jumper wire.
Using a DVM measure the voltage between the O2S 1 signal circuit and ground.

Does the O2S 1 voltage measure above specified value?

407 mV

Go to Step 12

Go to Step 13

Turn the ignition OFF.
Disconnect the PCM electrical connectors.
Check the O2S 1 low circuit for continuity.
Whenever the O2S 1 low circuit measures over the stated value, repair the open circuit or the poor connection as necessary. Refer to Wiring Repairs .

If an O2S 1 low circuit problem was found, was the problem corrected?

5 ohms

Go to Step 17

Go to Step 14

Turn the ignition OFF.
Disconnect the PCM electrical connectors.
Check the O2S 1 signal circuit for continuity.
Whenever the O2S 1 signal circuit measures over the stated value, repair the open circuit or the poor connection as necessary. Refer to Wiring Repairs .

If an O2S 1 signal circuit problem was found, was the problem corrected?

5 ohms

Go to Step 17

Go to Step 15

Check the O2S 1 low circuit terminal connection at the PCM.
Replace the terminal if necessary.

Did the terminal require replacement?

Go to Step 17

Go to Step 16

Check the O2S 1 signal circuit terminal connection at the PCM.
Replace the terminal if necessary.

Did the terminal require replacement?

Go to Step 17

Go to Step 16

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

Go to Step 17

Using the scan tool, clear the DTCs.
Start the Engine.
Allow the engine to idle until the engine reaches the specified temperature.
Operate the vehicle within the conditions for setting this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic ran and passed?

90°-95° C

Go to Step 18

Go to Step 2

Check if any additional DTCs are set.

Are any DTCs displayed that have not been diagnosed?

Go to the Applicable DTC Table

System OK