P2252
DTC P2252 or P2253
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) provides an overview of each diagnostic category.
DTC Descriptors
DTC P2252
- Heated Oxygen Sensor (HO2S) Low Reference Circuit Low Voltage Sensor 1
DTC P2253
- Heated Oxygen Sensor (HO2S) Low Reference Circuit High Voltage Sensor 1
Diagnostic Fault Information
Typical Scan Tool Data
Circuit Description
The heated oxygen sensor (HO2S) 1 is a wide band or wide range design. The wide band HO2S measures the amount of oxygen in the exhaust system, but provides more information than the typical 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 powertrain control module (PCM) 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 PCM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The PCM 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 PCM can determine the concentration of oxygen in the exhaust. The HO2S input signal is displayed as a voltage within the range of 1-5 volts, with a steady value of 3.2-3.3 volts equal to the air fuel ratio of 14.7:1. If the HO2S 1 input voltage is lower than the specified reference voltage, the PCM determines that the air/fuel ratio is richer than the theoretical air/fuel ratio and reduces the fuel. If the input voltage from the HO2S 1 is higher than the specified reference voltage, the PCM determines that the air/fuel ratio is leaner and increases the fuel. By repeating these operations, the PCM can adjust the air/fuel ratio in order to be closer to the theoretical air/fuel ratio. Control of the fuel delivery system as just described is known as Closed Loop operation.
Conditions for Running the DTC
* DTCs P0031, P0032, P0037, P0038, P0100, P0101, P0102, P0103, P0110, P0112, P0113, P0115, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0171, P0172, P0220, P0222, P0223, P0300-P0304, P0335, P0339, P0340, P0341, P0441, P0443, P0455, P0456, P0500, P2135 are not set.
* The battery voltage is greater than 10.5 volts.
* The engine coolant temperature (ECT) is greater than 20°C (68°F).
* The engine has been running for greater than 20 seconds.
* The DTCs run once per drive cycle when the above conditions have been met.
Conditions for Setting the DTC
P2252
The HO2S 1 low reference circuit voltage is less than 0.5 volts for greater than 5 seconds.
P2253
The HO2S 1 low reference circuit voltage is greater than 4.5 volts for greater than 5 seconds.
Action Taken when the DTC Sets
DTCs P2252 and P2253 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P2252 and P2253 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
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)
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. Engine running at normal operating temperature, observe the scan tool HO2S 1 voltage parameter. The reading should fluctuate between 3.2-3.4 V.
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. Ignition OFF, disconnect the harness connector at the HO2S 1.
2. Ignition ON, test for 2.9-3.2 V between the low reference circuit terminal 3 and ground.
• If less than the specified range, test the low reference circuit for a short to ground. If the circuit tests normal, replace the PCM.
• If greater than the specified range, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the PCM.
3. If all the circuits test normal, replace the HO2S 1.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Heated Oxygen Sensor Replacement - Sensor 1 (Heated Oxygen Sensor Replacement - Sensor 1)
* Control Module References (Programming and Relearning) for control module replacement, setup, and programming