DTC P2237-P2239, P2243, P2251, or P2626
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DTC P2237-P2239, P2243, P2251, or P2626
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DTC P2237
HO2S Pumping Current Control Circuit Sensor 1
DTC P2238
HO2S Pump Current Control Circuit Low Voltage Sensor 1
DTC P2239
HO2S Pump Current Control Circuit High Voltage Sensor 1
DTC P2243
HO2S Reference Voltage Circuit Sensor 1
DTC P2251
HO2S Low Reference Circuit Sensor 1
DTC P2626
HO2S Pumping Current Trim Circuit Sensor 1
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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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Heater Voltage Supply
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P0030, P0130
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P0030, P0053, P0130, P0135
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-
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Heater Low Control
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P0031, P0130
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P0030, P0053, P0135
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P0032
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Reference Voltage (Signal)
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P0131
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P0130, P2243
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P0132
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Low Reference (Ground)
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P0130, P0136
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P0130, P2251
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P0132
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Pump Current
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P0130, P0131, P2237
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P2237
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P0132, P2237
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Trim Current
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P0130, P0131, P2626
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P2626
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P0132, P2626
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Circuit/System Description
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The heated broadband oxygen sensor (HO2S) measures the quantity of oxygen in the exhaust stream faster and more accurately than an HO2S of a switching type. The broadband probe consists of a oxygen detection 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 signal 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 signal voltage. The ECM monitors the voltage variation on the signal circuit and attempts to keep the voltage constant by increasing or decreasing the amount of current flow or reversing the direction of the current flow to the pumping cell. By measuring the direction and amount of current required to maintain the signal voltage, the ECM can determine the concentration of oxygen in the exhaust. The signal 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 system is lean, the oxygen level will be high and the lambda value will be high, or more than 1. When the system is rich, the oxygen level is low and the lambda value will be low, or less than 1. The ECM uses this information to maintain the proper air/fuel ratio.
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Conditions for Running the DTC
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P2237
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DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, P0338 are not set.
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The ignition voltage is between 10.7-18.1 V.
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HO2S 1 voltage is between 1.48-1.52 V.
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The HO2S 1 heater is at operating temperature.
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HO2S 1 Closed Loop is active.
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The catalyst temperature is stable.
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DTC P2237 runs continuously when the above conditions are met for 2 s.
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P2238 and P2239
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The ignition voltage is between 10.7-18.1 V.
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DTCs P2238 and P2239 run continuously when the above conditions have been met for 1.5 s.
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P2243
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DTCs P0030, P0031, P0032 are not set.
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The ignition voltage is between 10.7-18.1 V.
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HO2S 1 heater is at operating temperature for at least 20 s.
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HO2S 1 internal resistance is more than 570 Ω.
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DTC P2243 runs continuously when the above conditions are met for 2 s.
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P2251
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DTCs P0030, P0031, P0032 are not set.
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The ignition voltage is between 10.7-18.1 V.
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The estimated exhaust temperature is less than 900°C (1,652°F).
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The HO2S 1 voltage is between 1.47-1.53 V.
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The HO2S 1 heater temperature has been within the normal range for more than 20 s.
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HO2S 1 internal resistance is more than 570 Ω.
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The following are true for more than 30 s.
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-
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The HO2S 1 heater is ready.
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-
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The ignition voltage is more than 11 V.
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DTC P2251 runs continuously when the above conditions are met for 10 minutes.
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P2626
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DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, P0338 are not set.
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The ignition voltage is between 10.7-8.1 V.
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The estimated exhaust temperature is less than 750°C (1,382°F).
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The HO2S 1 heater is at operating temperature.
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DTC P2626 runs continuously when the above conditions are met for 4 s, or when the above conditions are met for 10 minutes if the fuel level is low.
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Conditions for Setting the DTC
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P2237
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The ECM detects that the pumping current circuit is open.
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DTC P2237 sets within 4 s when the above condition is met continuously, or within 50 s when the above condition is met cumulatively.
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P2238
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The ECM detects that the HO2S 2 voltage is less than 1.7 V during deceleration fuel cut-off.
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DTC P2238 sets when the above condition has been met for 3 s.
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P2239
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The ECM detects that the HO2S 2 voltage is between 1.48-1.51 V during Closed Loop and fuel enrichment.
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DTC P2239 sets when the above condition has been met for 1 s.
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P2243
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The ECM detects that the HO2S 1 voltage is less than 0.2 V or more than 4.7 V.
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DTC P2243 sets within 4 s when the above condition is met continuously, or within 50 s when the above condition is met cumulatively.
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P2251
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The ECM detects that the reference ground circuit is open.
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DTC P2251 sets within 4 s when the above condition is met continuously, or within 50 s when the above condition is met cumulatively.
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P2626
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The ECM detects that the HO2S 1 voltage is more than 4.81 V.
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DTC P2626 sets within 4 s when the above condition is met continuously, or within 50 s when the above condition is met cumulatively.
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Action Taken When the DTC Sets
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DTCs P2237, P2238, P2239, P2243, P2251, and P2626 are Type B DTCs.
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Conditions for Clearing the DTC
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DTCs P2237, P2238, P2239, P2243, P2251, and P2626 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 to run and set the DTC. The DTC should not be set.
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3.
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Run the vehicle within the Conditions for Running the DTCs. You may also operate the vehicle within the conditions that you have noted from the Freeze Frame/Failure Records data.
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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 B52A HO2S 1.
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2.
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Ignition ON, test for 2.9 V between the signal circuit terminal 6 and ground.
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3.
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If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
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4.
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If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
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5.
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Ignition ON, test for 2.5 V between the signal circuit terminal 2 and ground.
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6.
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If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
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7.
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If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
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8.
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Ignition ON, test for 2.8 V between the current circuit terminal 1 and ground.
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9.
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If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
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10.
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If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
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11.
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Ignition ON, test for 2.8 V between the current circuit terminal 5 and ground.
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12.
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If more than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
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13.
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If less than the specified value, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
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14.
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Ignition OFF, disconnect the K20 ECM connector X1.
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15.
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Ignition OFF, test for infinite Ω between each B52A HO2S 1 circuit terminal listed below, and all other B52A HO2S 1 circuit terminals listed below:
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16.
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If less than the specified value, repair as necessary.
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17.
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If the K20 ECM and all circuits test normal, replace the B52A HO2S 1.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
