LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1577 (Engine Controls And Fuel - 3.5L (L66) - DTC P2227 To DTC P2649) >> DTC P2253 or P2256 >> 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 for a condition in the reference voltage circuit. Test for a short to voltage, if the voltage measures more than 4 volts.
  3. 5:  This step tests for a condition in the low reference circuit. Test for an open, a high resistance, or a short to voltage, if the voltage measures more or less than the specified value.
  4. 6:  This step tests for a condition in the input pump current circuit. Test for a short to voltage if the voltage measures more than 4 volts.
  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 be established.
DTC P2253 or P2256

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 P2253 is for bank 1 sensor 1 - rear and DTC P2256 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 appropriate heated oxygen sensor (HO2S) connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage between the HO2S reference voltage circuit and a good ground with a DMM.
Is the voltage less than the specified value?		 4 V Go to Step 5  Go to Step 7 
5  Measure the voltage between the HO2S low reference circuit and a good ground with a DMM.
Is the voltage within the specified range?		 5.9-6.4 V Go to Step 6  Go to Step 8 
6  Measure the voltage between the HO2S input pump current circuit and a good ground with a DMM.
Is the voltage more than the specified value?		 4 V Go to Step 9  Go to Step 10 
7 Test the reference voltage circuit of the HO2S for a short to voltage. 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 low reference circuit of the HO2S for an open, a high resistance, or a short to voltage. 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 input pump current circuit of the HO2S for a short to voltage. 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 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
scientia non olet · About LEMON Manuals