P0136
DTC P0136
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provide an overview of each diagnostic category.
DTC Descriptor
DTC P0136 00
- HO2S Circuit Sensor 2
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The heated oxygen sensor (HO2S) 2 circuit diagnostics monitors the voltage on the signal circuit of the post catalyst oxygen sensor. In order to control emissions of hydrocarbons, carbon monoxide (CO), and oxides of nitrogen (NOX), a 3-way catalytic converter is used. The catalyst within the converter promotes a chemical reaction which oxidizes the hydrocarbons and CO present in the exhaust gas, converting the hydrocarbons and the CO into harmless water vapor and carbon dioxide. The catalyst also reduces NOX by converting the NOX to nitrogen. The engine control module (ECM) has the ability to monitor this process using the heated oxygen sensors HO2S 1 and heated oxygen sensor (HO2S) 2. The heated oxygen sensor (HO2S) 1 produces an output signal which indicates the amount of oxygen present in the exhaust gas entering the 3-way catalytic converter. The heated oxygen sensor (HO2S) 2 produces an output signal which indicates the oxygen storage capacity of the catalyst. This in turn indicates the catalysts ability to convert exhaust gases efficiently. If the catalyst is operating efficiently, the heated oxygen sensor (HO2S) 1 signal will be far more active than that produced by the heated oxygen sensor (HO2S) 2.
The HO2S utilizes the following circuits:
* A signal circuit
* A low reference circuit
* An ignition voltage circuit
* A heater control circuit
Conditions for Running the DTC
P0136 00
* DTC P0031 00, P0032 00, P0037 00, P0038 00, P0112 00, P0113 00, P0117 00, P0118 00, P0121 00, P0122 00, P0123 00, P0125 00, P0171 00, P0172 00, P0300 00 - P0304 00, P0335 00, P0340 00, P0341 00, P0455 00, P0456 00, P0500 00, P2A00 00 are not set.
* The battery voltage is greater than 11 V.
* The engine coolant temperature (ECT) is greater than or equal to 75°C (167°F).
* The engine speed is between 1600-4000 RPM.
* The engine is operating in closed loop fuel control.
* DTC P0136 00 runs once per drive cycle when the above conditions are met for 2 s.
Conditions for Setting the DTC
P0136 00
* The average heated oxygen sensor (HO2S) 2 voltage is greater than or equal to 600 mV.
or
* The average heated oxygen sensor (HO2S) 2 voltage is less than or equal to 250 mV.
Action Taken When the DTC Sets
DTCs P0136 00 is a Type B DTCs.
Conditions for Clearing the DTC
DTCs P0136 00 is a Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
* Heated Oxygen Sensor Wiring Repairs (Heated Oxygen Sensor Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Circuit/System Verification
1. Clear the DTCs with a scan tool.
2. Operate the vehicle within the conditions for running and setting the DTC. The DTC should not set.
Circuit/System Testing
Note: You must perform the Circuit/System Verification before proceeding with Circuit/System testing.
1. Ignition OFF, disconnect the harness connector at the B52B Heated Oxygen Sensor 2.
2. Ignition OFF, measure for less than 5 ohm between the B52B Heated Oxygen Sensor 2 low signal circuit terminal 4 and ground.
• If more than the specified range, test the appropriate HO2S low signal circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
3. Ignition ON, verify the appropriate scan tool HO2S parameter is approximately 450 mV.
• If more than the specified value, test the appropriate B52B Heated Oxygen Sensor 2 high signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
• If less than the specified value, test the appropriate B52B Heated Oxygen Sensor 2 high signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
4. Ignition ON, install a 3 A fused jumper wire at the B52B Heated Oxygen Sensor 2 high signal circuit terminal 2. Toggle the jumper wire between the B52B Heated Oxygen Sensor 2 low signal circuit terminal 4 and battery voltage. Verify the appropriate scan tool HO2S 2 parameter toggles between 0 mV and approximately 1000 mV.
• If the appropriate scan tool B52B Heated Oxygen Sensor 2 parameter does not toggle correctly, test the B52B Heated Oxygen Sensor 2 high signal circuit terminal 2 for an open/high resistance. If the circuits test normal, replace the K20 Engine Control Module.
5. If all circuits test normal, replace the appropriate B52B Heated Oxygen Sensor 2.
Repair Instructions
Caution: Refer to Heated Oxygen Sensor Resistance Learn Reset Caution (Heated Oxygen Sensor Resistance Learn Reset Caution).
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Heated Oxygen Sensor Replacement - Sensor 2 (Heated Oxygen Sensor Replacement - Sensor 2)
* Control Module References (Programming and Relearning)for ECM replacement, setup, and programming