GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 HUMMER 🢒 2007 🢒 H3 🢒 DTC 🢒 DTC P0130, P0131, P0132, P0133, P0134, P0136, P0137, P0138, P0140, P1133, or P1134

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0130: HO2S Circuit Closed Loop (CL) Performance Sensor 1

DTC P0131: HO2S Circuit Low Voltage Sensor 1

DTC P0132: HO2S Circuit High Voltage Sensor 1

DTC P0133: HO2S Slow Response Sensor 1

DTC P0134: HO2S Circuit Insufficient Activity Sensor 1

DTC P0136: HO2S Circuit Sensor 2

DTC P0137: HO2S Circuit Low Voltage Sensor 2

DTC P0138: HO2S Circuit High Voltage Sensor 2

DTC P0140: HO2S Circuit Insufficient Activity Sensor 2

DTC P1133: HO2S Insufficient Switching Sensor 1

DTC P1134: HO2S Transition Time Ratio Sensor 1

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

HO2S High Signal

P0130, P0131, P0132, P0136, P0137, P0140, P1133

P0130, P0131, P0132, P0133, P0134, P0136, P0137, P0140, P1133, P1134

P0130, P0131, P0132, P0133, P0134, P0136, P0137, P0140, P1133, P1134

P0130, P0132, P0134, P0136, P0138, P0140, P1133

P0130, P0133, P0134, P0140, P1133

HO2S Low Signal

P0130, P0136

P0130, P0131, P0132, P0133, P0134, P0136, P0138, P0140, P1133, P1134

P0130, P0131, P0132, P0133, P0134, P0136, P0138, P0140, P1133, P1134

P0130, P0134, P0136, P0138, P0140, P1133

P0130

Typical Scan Tool Data

HO2S Sensor 1 Voltage

Circuit

Normal Range

Short to Ground

Open

Short to Voltage

HO2S High Signal

200-800 mV

0 mV

Approximately 470 mV

Approximately 1,100 mV

HO2S Low Signal

200-800 mV

455 mV

Approximately 450 mV

Approximately 445 mV

Circuit/System Description

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the PCM operates in open loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream, low HO2S voltage indicates a lean exhaust stream.

P0136

The HO2S 2 is used for catalyst monitoring. This diagnostic runs once per ignition cycle. This diagnostic consists of two tests, a passive test and an intrusive test. During the passive test, if the HO2S 2 voltage transitions below 300 mV and above 650 mV, the DTC will pass for this ignition cycle. If the DTC does not pass during the passive test, the intrusive test will begin. During the intrusive test, the control module will force the air-to-fuel ratio rich and/or lean. The control module then waits for a predicted response from the HO2S 2. If the HO2S 2 voltage transitions below 300 mV and/or above 650 mV, the DTC will pass for this ignition cycle.

Conditions for Running the DTC

P0130

    • DTC P0030, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0442, P0451, P0452, P0453, P0454, P1106, P1107, P1114, P1115, P1120, P1133, P1134, P1220, P1221, P1271, P1275, P1280, P1380, P1381, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Engine Run Time parameter is more than 200 seconds.
    • The Engine speed parameter is between 1,000-3,000 RPM.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Mass Airflow (MAF) Sensor parameter is between 10-50 g/s.
    • The Engine Coolant Temperature (ECT) Sensor parameter is more than 70°C (158°F).
    • The traction control is not active.
    • The catalyst protection mode is not active.
    • The decel fuel cut-off is not active.
    • The power enrichment is not active.
    • The engine metal overtemp is not active.
    • DTC P0130 runs continuously when the above conditions are met for 2 seconds.

P0131 Lean Test Enable

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Loop Status parameter is Closed.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • The Throttle Position (TP) Indicated Angle parameter is between 15-50 percent.
    • The catalyst diagnostic test is not active.
    • Traction control is not active.
    • The air/fuel ratio is between 14.5-14.8.
    • DTC P0131 runs the lean test continuously when the above conditions are met for 2 seconds.

P0131 Power Enrichment Test Enable

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • Power enrichment mode is enabled.
    • The catalyst diagnostic test is not active.
    • Traction control is not active.
    • DTC P0131 runs the power enrichment test continuously when the above conditions are met for 2 seconds.

P0132 Rich Test Enable

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Loop Status parameter is Closed.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • The Throttle Position (TP) Sensor parameter is between 0-50 percent.
    • The catalyst test is not active.
    • Traction control is not active.
    • The air/fuel ratio is between 14.5-14.8.
    • DTC P0132 runs the rich test continuously when the above conditions are met for 2 seconds.

P0132 Decel Fuel Cutoff Test Enable

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • The decel fuel cutoff mode is enabled.
    • The catalyst test is not active.
    • Traction control is not active.
    • DTC P0132 runs the decel fuel cutoff test continuously when the above conditions are met for 2 seconds.

P0133

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Engine Coolant Temperature (ECT) Sensor parameter is more than 70°C (158°F).
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • The Engine Run Time parameter is more than 200 seconds.
    • The Engine Speed parameter is between 1,000-3,500 RPM.
    • The Mass Airflow (MAF) Sensor parameter is between 15-50 g/s.
    • The Loop Status parameter is Closed.
    • The Throttle Position (TP) Indicated Angle parameter is more than 5 percent.
    • The catalyst test is not active.
    • Traction control is not active.
    • No fuel injectors are disabled.
    • The transmission is not in Park, Reverse, or Neutral.
    • DTC P0133 runs once per drive cycle when the above conditions are met for 2 seconds.

P0134

    • DTCs P0030, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0135, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The catalyst diagnostic test is not active.
    • Traction control is not active.
    • The engine run time is more than 200 seconds.
    • The throttle position sensor transitions more than one percent, more than 2 times.
    • DTC P0134 runs continuously when the above conditions are met.

P0136 Passive Test

    • DTCs P0030, P0036, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1133, P1134, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The engine is running.
    • The system voltage is between 11-18 volts.
    • The Engine Run Time parameter is equal to or more than 2 seconds.
    • DTC P0136 runs the passive test once per drive cycle when the above conditions are met.

P0136 Intrusive Test

    • DTCs P0030, P0036, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1133, P1134, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Engine Run Time parameter is more than 12 minutes.
    • The ignition 1 Signal parameter is between 11-18 volts.
    • The MAF sensor parameter is between 10-100 g/s.
    • The Engine Speed parameter is between 1,000-5,000 RPM.
    • The Vehicle Speed parameter is between 30-130 km/h (19-81 mph).
    • The Short Term FT parameter is between -5 and +8 percent.
    • The passive test did not pass.
    • The EVAP diagnostic is not controlling purge.
    • The system is in Closed loop.
    • DTC P0136 runs the intrusive test once per drive cycle when the above conditions are met.

P0137 Lean Test Enable

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0442, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Loop Status parameter is Closed.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • The TP Sensor parameter is between 15-50 percent.
    • The catalyst diagnostic test is not active.
    • The traction control is not active.
    • The air-to-fuel ratio is between 14.5-14.8.
    • DTC P0137 runs the lean test continuously when the above conditions are met for 2 seconds.

P0137 Power Enrichment Test Enable

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0442, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • The Engine Run Time parameter is more than 200 seconds.
    • The Power Enrichment parameter is active.
    • The catalyst diagnostic test is not active.
    • The traction control is not active.
    • DTC P0137 runs the power enrichment test continuously when the above conditions are met for 3 seconds.

P0138 Rich Test Enable

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Loop Status parameter is Closed.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • The TP Sensor parameter is between 0-50 percent.
    • The catalyst diagnostic test is not active.
    • The traction control is not active.
    • The air-to-fuel ratio is between 14.5-14.8.
    • The throttle position is between 15-50 percent.
    • DTC P0138 runs the rich test continuously when the above conditions are met for 2 seconds.

P0138 Decel Fuel Cutoff Test Enable

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • The decel fuel cut-off (DFCO) is active.
    • The catalyst diagnostic test is not active.
    • The traction control is not active.
    • The air-to-fuel ratio is between 14.5-14.8.
    • The throttle position is between 15-50 percent.
    • DTC P0138 runs the decel fuel cutoff test continuously when the above conditions are met for 3 seconds.

P0140

    • DTCs P0036, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0141, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0442, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The ECT Sensor parameter is more than 70°C (158°F).
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The Engine Run Time parameter is more than 200 seconds.
    • The Loop Status parameter is closed.
    • The catalyst diagnostic test is not active.
    • The traction control is not active.
    • The Engine Run time is more than 200 seconds.
    • The throttle position sensor transitions more than one percent, more than 2 times.
    • DTC P0140 runs once per drive cycle when the above conditions are met.

P1133

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The ECT Sensor parameter is more than 70°C (158°F).
    • The catalyst diagnostic test is not active.
    • The Engine Speed parameter is between 1,500-3,500 RPM.
    • The traction control is not active.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • The transmission is not in Park, Neutral, or Reverse.
    • The Engine Run Time parameter is more than 200 seconds.
    • The Loop Status parameter is Closed.
    • The TP Indicated Angle parameter is more than 5 percent.
    • The Fuel Level Sensor parameter is more than 10  percent.
    • The MAF Sensor parameter is between 15-50 g/s.
    • DTC P1133 runs once per drive cycle when the above conditions are met for 2 seconds.

P1134

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0223, P0300, P0440, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1336, P1380, P1381, P1441, P1514, P1631, P1680, P1681, P2122, P2123, P2127, P2128 are not set.
    • The ECT Sensor parameter is more than 70°C (158°F).
    • The catalyst diagnostic test is not active.
    • The Engine Speed parameter is between 1,000-3,500 RPM.
    • The traction control is not active.
    • The Ignition 1 Signal parameter is between 11-18 volts.
    • No fuel indicators are disabled.
    • The Engine Run Time parameter is more than 200 seconds.
    • The Loop Status parameter is Closed.
    • The TP Sensor parameter is equal to or more than 5 percent.
    • The transmission is not in Park, Neutral, or Reverse.
    • The Fuel Level Sensor parameter is more than 10 percent.
    • The Air Flow Calculated parameter is between 15-50 g/s.
    • DTC P1134 runs once per drive cycle when the above conditions are met for 2 seconds.

Conditions for Setting the DTC

P0130

    • The control module detects that the Loop Status parameter is open.
    • DTC P0130 sets within 50 seconds when the above condition is met.

P0131 Lean Test

    • The control module detects that the HO2S 1 Voltage parameter is less than 50 mV.
    • DTC P0131 sets within 100 seconds during the lean test when the above condition is met.

P0131 Power Enrichment Test

    • The control module detects that the HO2S 1 Voltage parameter is less than 550 mV.
    • DTC P0131 sets within 100 seconds during the power enrichment test when the above condition is met.

P0132 Rich Test

    • The control module detects that the HO2S 1 parameter is more than 1,000 mV.
    • DTC P0132 sets within 15 seconds during the rich test when the above condition is met.

P0132 Decel Fuel Cutoff Test

    • The control module detects that the HO2S 1 parameter is more than 350 mV.
    • DTC P0132 sets within 40 seconds during the decel fuel cutoff test when the above condition is met.

P0133

    • The control module detects that the HO2S 1 rich-to-lean or lean-to-rich average response time is more than 0.2 second.
    • DTC P0133 sets within 60 seconds when the above condition is met.

P0134

    • The control module detects that the HO2S 1 parameter is between 400-500 mV.
    • DTC P0134 sets within 100 seconds when the above conditions are met.

P0136

  1. The control module detects that the HO2S 2 did not transition below 250 mV and above 650 mV during the passive test.
  2. One of the following tests fail:

    3. Lean Intrusive Test

    • The control module detects that the HO2S 2 is more than 250 mV for 10 seconds.
    • The HO2S 1 is less than 350 mV.

    Rich Intrusive Test

    • The control module detects that the HO2S 2 is less than 650 mV for 10 seconds.
    • The HO2S 1 is more than 550 mV.
  3. DTC P0136 sets within 7 minutes when the above conditions are met.

P0137 Lean Test

    • The control module detects that the HO2S 2 voltage parameter is less than 50 mV.
    • DTC P0137 sets within 100 seconds during the lean test when the above condition is met.

P0137 Power Enrichment Test

    • The control module detects that the HO2S 2 voltage parameter is less than 650 mV and the HO2S 1 parameter is more than 700 mV.
    • DTC P0137 sets within 10 seconds during the power enrichment test when the above condition is met.

P0138 Rich Test

    • The control module detects that the HO2S 2 voltage parameter is more than 1,000 mV.
    • DTC P0138 sets within 100 seconds during the rich test when the above condition is met.

P0138 Decel Fuel Cutoff Test

    • The control module detects that the HO2S 2 voltage parameter is more than 300 mV.
    • DTC P0138 sets within 10 seconds during the decel fuel cutoff test when the above condition is met.

P0140

    • The control module detects that the HO2S 2 parameter is between 425-475 mV.
    • DTC P0140 sets within 100 seconds when the above conditions are met.

P1133

    • The control module detects that the HO2S 1 rich-to-lean counts, or the lean-to-rich counts are less than a calibrated value.
    • DTC P1133 sets within 60 seconds when the above condition is met.

P1134

    • The PCM detects that the difference between the HO2S 1 rich-to-lean average transition time and the lean-to-rich average transition time is more than a calibrated value.
    • DTC P1134 sets within 60 seconds when the above condition is met.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Powertrain Control Module Connector End Views
    •  Engine Controls Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Heated Oxygen Sensor Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification
    • Allow the engine to reach operating temperature. With the engine running, observe the affected HO2S parameter with a scan tool.
       -  The HO2S 1 value should vary from below 200 mV to above 800 mV and respond to fueling changes.
       - The HO2S 2 value should change more than 200 mV when the throttle is quickly cycled 3 times from closed to wide open and back to closed after running the engine at 1500 RPM for 30 seconds.
    • With the engine running at operating temperature, observe the affected HO2S parameter with a scan tool and manipulate the related wiring and connectors. Manipulation should not affect the parameter.
       ⇒If manipulation does affect the parameter then repair the harness or connector.
    • If any HO2S heater DTCs are set then diagnose those DTCs first.
    • The affected HO2S may be damaged due to contamination. Prior to replacing the affected HO2S, inspect for the following sources of contamination:

Notice: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in the Preface section.

       - A silicon contaminated HO2S
       - Fuel contamination--Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
       - Engine oil consumption--Refer to Oil Consumption Diagnosis .
       - Engine coolant consumption--Refer to Loss of Coolant .

Circuit/System Testing
  1. With the ignition ON, the engine OFF, and the sensor disconnected, measure for approximately 45 mV from the affected HO2S low signal circuit terminal A to ground.
    2. ⇒If more than approximately 45 mV, test the affected HO2S low signal circuit for a short to voltage. If the circuit tests normal, replace the PCM.
    ⇒If less than approximately 45 mV, test the affected HO2S low signal circuit for an open/high resistance. If the circuit tests normal, replace the PCM.
  2. With the ignition ON, the engine OFF, and the sensor disconnected, measure for approximately 450 mV from the affected HO2S high signal circuit terminal B to ground.
    3. ⇒If more than approximately 450 mV, test the affected HO2S High Signal circuit and the affected HO2S low signal circuit for a short to voltage. If the circuit tests normal, replace the PCM.
    ⇒If less than approximately 450 mV, test the affected HO2S high signal circuit for an open/high resistance. If the circuit tests normal, replace the PCM.
  3. With the ignition ON, the engine OFF, and the sensor disconnected, install a 3A fused jumper between the affected HO2S high signal circuit terminal B and the affected HO2S low signal circuit terminal A. The affected HO2S parameter should indicate 0 mV.
    4. ⇒If all circuits and connectors test normal and the affected HO2S parameter does not indicate 0 mV, replace the PCM.
  4. With the ignition ON, the engine OFF, and the sensor disconnected, install a test lamp between the affected HO2S high signal circuit terminal B and battery voltage. The affected HO2S parameter should indicate approximately 1,095 mV.
    5. ⇒If all circuits and connectors test normal and the affected HO2S parameter does not indicate 1,095 mV, replace the PCM.
  5. If the PCM and all circuits test normal, replace the affected HO2S.

Repair Instructions

Notice: Refer to Heated Oxygen Sensor Resistance Learn Reset Notice in the Preface section.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Heated Oxygen Sensor 1 Replacement
    •  Heated Oxygen Sensor 2 Replacement
    •  Control Module References for replacement, setup, and programming