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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1870 (Engine Controls And Fuel - 3.5L (L66) - DTC P2227 To DTC P2649) >> DTC P2238 or P2241 >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  This step determines whether a condition currently exists. If the lambda value fluctuates near 1.00 and Loop Status is Closed, the HO2S is operating correctly.
  2. 4:  This step tests the input pump current circuit. Test the input pump current circuit for a short to ground if the voltage is less the specified value.
  3. 5:  This step tests for a condition in the pump current circuit. If the voltage is less than 4.8 volts, test for a wire to wire short to the heater control circuit.
  4. 6:  This step isolates the condition. Test for a wire to wire short between the heater control circuit and the input pump current circuit of the HO2S if the voltage on the heater control circuit is more than 1 volt.
  5. 10:  Inspect the HO2S connector for water intrusion, corrosion, and bent or damaged terminals.
  6. 11:  Inspect the PCM connectors for water intrusion, corrosion, and bent or damaged terminals.
  7. 13:  After replacing the PCM, a new minimum throttle position and idle speed must also be established.
DTC P2238 or P2241

Step Action Values Yes No
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
IMPORTANT: DTC P2238 is for bank 1 sensor 1 - rear and DTC P2241 is for bank 2 sensor 1 - front
  1. Allow the engine to reach operating temperature.
  2. Observe the Loop Status Bank 1 or Loop Status Bank 2 with a scan tool.
Does the scan tool display Closed Loop?		 - Go to Step 3  Go to Step 4 
3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 4  Go to Diagnostic Aids
4 
  1. Turn OFF the ignition.
  2. Disconnect the affected heated oxygen sensor (HO2S).
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage between the HO2S input pump current circuit and a good ground with a DMM.
Is the voltage within the specified range?		 3.3-3.8 V Go to Step 5  Go to Step 7 
5  Measure the voltage between the HO2S pump current circuit and a good ground with a DMM.
Is the voltage more than the specified value?		 4.8 V Go to Step 6  Go to Step 9 
6  Measure the voltage between the HO2S heater control circuit and a good ground with a DMM.
Is the voltage more than the specified value?		 1.0 V Go to Step 8  Go to Step 10 
7 Test the input pump current circuit of the HO2S for a short to ground or a short to the reference ground circuit of the HO2S. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 14  Go to Step 11 
8 Test the input pump current circuit of the HO2S for a short to the heater control circuit of the HO2S. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 14  Go to Step 11 
9 Test the pump current circuit of the HO2S for a short to the heater control circuit of the HO2S. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 14  Go to Step 11 
10  Test for shorted terminals and for poor connections at the HO2S sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 14  Go to Step 12 
11  Test for shorted terminals and for poor connections at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 14  Go to Step 13 
12 Replace the HO2S sensor. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 or Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .
Did you complete the replacement?		 - Go to Step 14  -
13 
  1. Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
  2. Perform the idle learn procedure. Refer to Idle Learn .
Did you complete the replacement?		 - Go to Step 14  -
14
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 90 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 15 
15 In order to ensure that the performance of the catalyst has not been affected by the fault that set this DTC, operate the vehicle within the conditions for running and setting DTC P0420/0430 and verify that DTC P0420/0430 runs and passes. Refer to DTC P0420 or P0430 .
Does the DTC run and pass?		 - Go to Step 16  Go to DTC P0420 or P0430
16 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List - Vehicle System OK
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