DTC P0036, P0037, P0038, or P0141 (LLU)
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DTC P0036, P0037, P0038, or P0141 (LLU)
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DTC P0036 00
HO2S Heater Control Circuit Sensor 2
DTC P0037 00
HO2S Heater Control Circuit Low Voltage Sensor 2
DTC P0038 00
HO2S Heater Control Circuit High Voltage Sensor 2
DTC P0141 00
HO2S Heater Performance Sensor 2
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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Ignition Voltage
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P0030 00, P0033 00, P0036 00, P0102 00, P0135 00, P0141 00
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P0036 00, P0037 00, P0141 00
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P0141 00
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Heater Low Control
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P0036 00, P0037 00,
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P0036 00, P0037 00, P0038 00, P0141 00
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P0036 00, P0038 00, P0141 00
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P0141 00
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Signal Circuit
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P0137 00
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P0138 00, P0141 00
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-
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P0140 00, P2270 00, P2271 00
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Circuit/System Description
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The heated oxygen sensors 1 or 2 are used for fuel control and catalyst monitoring. Each heated oxygen sensor compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an open loop mode, ignoring the heated oxygen sensor signal voltage while calculating the air to fuel ratio. The control module supplies the heated oxygen sensor with a reference, or bias voltage of about 450 mV. While the engine runs, each heated oxygen sensor heats up and begins to generate a voltage within a range of 0-1000 mV. This voltage will fluctuate above and below the bias voltage. Once sufficient heated oxygen sensors 1 or 2 voltage fluctuation is observed by the control module, closed loop is entered. The control module uses the heated oxygen sensor voltage to determine the air to fuel ratio. An heated oxygen sensor voltage that increases above bias voltage toward 1000 mV indicates a rich fuel mixture. An heated oxygen sensor voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture.
The heating elements inside each heated oxygen sensor heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter closed loop earlier and the control module to calculate the air to fuel ratio sooner.
P0036 00
The ECM monitors the voltage on the heated oxygen sensor 2 heater low control circuit for heater fault diagnosis. If the ECM detects that the heated oxygen sensor 2 heater low control circuit voltage is not within a specified range, DTC P0036 00 sets.
P0037 00
The ECM monitors the voltage on the heated oxygen sensor 2 heater low control circuit for heater fault diagnosis. If the ECM detects that the heated oxygen sensor 2 heater low control circuit voltage is below a specified range, DTC P0037 00 sets.
P0038 00
The ECM monitors the voltage on the heated oxygen sensor 2 heater low control circuit for heater fault diagnosis. If the ECM detects that the heated oxygen sensor 2 heater low control circuit voltage is above a specified range, DTC P0038 00 sets.
P0141 00
If the ECM detects that the heated oxygen sensor 2 heater current is not within the expected range, DTC P0141 00 sets.
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Conditions for Running the DTC
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P0036 00, P0037 00, and P0038 00
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The engine speed is greater that 40 RPM.
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The ignition voltage is between 8-16 V.
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DTC P0036 00, P0037 00, and P0038 00 run continuously when the above conditions are met for 1 s.
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P0141 00
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DTCs P0036 00, P0037 00, or P0038 00, are not set.
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The engine speed is greater that 25 RPM
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The ignition voltage is between 11-18 V.
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DTC P0141 00 runs continuously.
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Conditions for Setting the DTC
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P0036 00, P0037 00, and P0038 00
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The ECM detects that the difference between the expected and the actual heated oxygen sensor 2 heater low control circuit voltage is more than a calibrated value for 0.5 s.
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DTCs P0036 00, P0037 00, and P0038 00 set when the above condition is met.
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P0141 00 Heater Resistance Test
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The ECM detects that the heated oxygen sensors 2 heater resistance is more than a calibrated value for 20 s.
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DTC P0141 00 sets within 30 s during the heater current test when the above condition is met.
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Action Taken When the DTC Sets
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DTC P0036 00, P0037 00, P0038 00, P0141 00 are Type B DTCs.
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Conditions for Clearing the DTC
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DTC P0036 00, P0037 00, P0038 00, P0141 00 are Type B DTCs.
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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1.
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Clear the DTCs with a scan tool.
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2.
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Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that are captured in the freeze frame/failure records data.
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Note
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You must perform the circuit/system verification before proceeding with circuit/system testing.
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1.
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Ignition OFF, disconnect the harness connector at the B52B Heated Oxygen Sensor 2.
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2.
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Ignition ON, test for B+ between the B52B Heated Oxygen Sensor 2 ignition voltage circuit terminal 1 and ground.
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3.
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If less than the specified range, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition voltage circuit fuse F11 is open, test all components connected to the ignition voltage circuit and replace as necessary.
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4.
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Connect a test lamp between the B52B Heated Oxygen Sensor 2 heater control circuit terminal 2 and B+. The test lamp should not illuminate.
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5.
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If the test lamp is always ON, test the control circuit for a short to ground. If the circuit test normal, replace the K20 Engine Control Module.
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6.
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Idle the engine, and verify the test lamp illuminates or flashes.
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7.
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If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit/connections test normal, replace the K20 Engine Control Module.
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8.
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Ignition ON, test for 2-3 V between the B52B Heated Oxygen Sensor 2 control circuit terminal 2 and ground.
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9.
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If less than the specified range, test the control circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
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10.
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If greater than the specified range, test the control circuit for a short to voltage. If the circuit/connections test normal, replace the K20 Engine Control Module.
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11.
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If all circuits test normal, test or replace the B52B Heated Oxygen Sensor 2.
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Static Test
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1.
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Ignition OFF, disconnect the harness connector at the B52B Heated Oxygen Sensor 2.
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2.
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Test for 8-20 Ω between the B52B Heated Oxygen Sensor 2 ignition voltage circuit terminal 1 and the control circuit terminal 2.
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3.
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If not within the specified range, replace the B52B Heated Oxygen Sensor 2.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
