P2196
DTC P2196 or P2198
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P2196
- HO2S Signal Biased Rich Bank 1 Sensor 1
DTC P2198
- HO2S Signal Biased Rich Bank 2 Sensor 1
Circuit Description
The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the lambda signal will be high or greater than 1. When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio. If the ECM detects that the HO2S signal voltage is low, this DTC sets.
Conditions for Running the DTC
Condition 1
* Before the ECM can report DTC P2196 or P2198 failed, DTCs P0036, P0037, P0038, P0056, P0057, P0058, P0130, P0137, P0138, P0140, P0150, P0157, P0158, P0160, P064D, P064E, P2231, P2232, P2234, P2235, P2270, P2271, P2272, P2273, P2297, and P2298, must run and pass.
* DTC P0030, P0031, P0032, P0050, P0051, P0052, P0131, P0132, P0135, P0141, P0151, P0152, P0155, P0161, P2237, P2240, P2243, P2247, P2251, P2254, P2626, or P2629 is not set.
* The engine is operating.
* The engine speed and load are steady.
* The Closed Loop fuel control is active.
* The engine has cycled ON and OFF greater than 29 times.
* The fuel system is not in decel fuel cut-off (DEFCO)
* Catalyst heating or catalyst clear-out is not active.
* The cumulative mass air flow (MAF) into the engine is greater than 150 grams.
* The MAF is between 6-39 g/s
* The calculated exhaust temperature is between 350-850°C (662-1,562°F).
* The HO2S 1 Lambda is less than 1.000.
* HO2S 2 signal voltage is greater than 400 mV.
* DTC P2196 and P2198 run continuously once the above conditions are met.
Condition 2
* Before the ECM can report DTC P2196 or P2198 failed, DTCs P0036, P0037, P0038, P0056, P0057, P0058, P0130, P0137, P0138, P0140, P0150, P0157, P0158, P0160, P064D, P064E, P2231, P2232, P2234, P2235, P2270, P2271, P2272, P2273, P2297, and P2298, must run and pass.
* DTC P0030, P0031, P0032, P0050, P0051, P0052, P0131, P0132, P0135, P0141, P0151, P0152, P0155, P0161, P2237, P2240, P2243, P2247, P2251, P2254, P2626, or P2629 is not set.
* The HO2S 1 are in Closed Loop.
* The air flow into the engine is greater than 40 grams in each of a total of 7 auto-starts.
* The calculated exhaust gas temperature of the HO2S 1 is warmer than 720°C (1,328°F).
* The HO2S 1 Lambda is greater than 1.000.
* The HO2S 2 signal is greater than 600 mV.
* DTCs 2196 and P2198 run continuously when the conditions above have been met.
Conditions for Setting the DTC
* The ECM detects that the an HO2S 2 is operating too lean while the ECM is commanding a rich air/fuel mixture for greater than 4 seconds.
OR
* The ECM detects that an HO2S 1 is operating too rich while the corresponding HO2S 2 is operating too lean and the ECM detects that the fuel trim is at minimum control. The condition exists for greater than 4 seconds.
Action Taken When the DTC Sets
DTCs P2196 and P2198 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P2196 and P2198 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool DTC information. Verify DTC P0137, P0138, P0140, P0157, P0158, or P0160 is not also set.
• If any of the above DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
Warning: Refer to Road Test Warning (Road Test Warning).
Note: The rear heated oxygen sensor (HO2S) must be in closed loop for this diagnostic to run. A road load condition is necessary to obtain closed loop.
2. 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 you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Verify that none of the following conditions exist:
* Inspect the appropriate HO2S 1 and HO2S 2 for being secure
* Damaged wiring between either HO2S and the ECM
* Leaking fuel injectors-Refer to Fuel Injector Solenoid Coil Test (Fuel Injector Solenoid Coil Test)
* High fuel system pressure-Refer to Fuel System Diagnosis (Fuel System Diagnosis)
* Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) (Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool))Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) (Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool))
* Contaminated HO2S-Silicon
• If you find any of the above conditions, repair as necessary.
2. Ignition OFF, disconnect the harness connector at the appropriate HO2S 2.
3. Ignition ON, verify the scan tool HO2S 2 voltage parameter is between 400-520 mV.
• If greater than the specified range, test the HO2S 2 signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
4. Connect the harness connector at the HO2S 2.
5. Engine idling, raise the engine speed above 1,200 RPM for 30 seconds. Verify the scan tool HO2S 2 voltage parameter is less than 1,000 mV.
• If greater than the specified range, replace the HO2S 2.
6. Engine idling, move the HO2S 1 and HO2S 2 harnesses between the HO2S harness connector and the ECM. Observe the scan tool HO2S 1 lambda parameter, and the HO2S 2 voltage parameter. Verify the parameters do not change abruptly.
• If the parameter changes abruptly, repair the harness/connections as necessary.
7. If all circuits/connections test normal, replace the appropriate HO2S 1.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (Service and Repair)
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (Service and Repair)
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (Service and Repair)
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (Service and Repair)
* Control Module References (Programming and Relearning) for engine control module replacement, setup, and programming