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Home >> Cadillac >> 2006 >> STS Base, 3.6 7, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 16 (Engine Control System - 4.6L (LH2) - DTC P2138 To P2636) >> DTC P2237 or P2240 >> Conditions for Clearing the MIL/DTC

Conditions for Clearing the MIL/DTC

WARNING: This page is about a different variant/trim than selected.
DTC P2237 or P2240

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2 If DTC P0131 or P0151 is also set, diagnose those DTCs first.
Is DTC P0131 or P0151 also set?
- Go to DTC P0131 or P0151 Go to Step 3 
3
  1. Start the engine.
  2. Allow the engine to reach operating temperature. Refer to Scan Tool Data List .
  3. Cycle the throttle from idle to wide open throttle (WOT) 3 times within 5 seconds while observing the HO2S Bank 1 Sensor 1 or HO2S Bank 2 Sensor 1 parameter with a scan tool.
Does the affected lambda value reach the specified value as the engine decelerates?
1.989 Go to Step 4  Go to Step 5 
4
  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 5  Go to Intermittent Conditions
5
  1. Turn OFF the ignition.
  2. Inspect the exhaust system for any leaks upstream from the affected oxygen sensor.
  3. Inspect for any exhaust leaks between the heated oxygen sensor (HO2S) 1 and the HO2S 2.
  4. Repair the exhaust leak, as necessary. Refer to Exhaust Leakage in Engine Exhaust.
Did you find and correct the condition?
- Go to Step 15  Go to Step 6 
6
  1. Disconnect the connector for the HO2S that applies to this DTC.
  2. Visually and physically inspect for the following items:
    • The HO2S is securely installed.
    • Terminal corrosion or water intrusion
    • Terminal tension at the HO2S connectors
    • Damaged wiring
  3. Repair as necessary. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 15  Go to Step 7 
7
  1. Connect a 3-amp fused jumper wire between the HO2S input pump current circuit, on the engine harness side, and a good ground.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the HO2S Bank 1 Sensor 1 or HO2S Bank 2 Sensor 1 parameter with a scan tool.
Is the lambda value more than the specified value?
1.060 Go to Step 8  Go to Step 9 
8
  1. Remove the jumper wire from the previous step.
  2. Connect a 3-amp fused jumper wire between the HO2S low reference circuit and the HO2S reference voltage circuit, on the engine harness side.
  3. Measure the voltage from the HO2S output pump current circuit, on the engine harness side connector, to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.
Is the voltage more than the specified value?
4.5 V Go to Step 11  Go to Step 10 
9 Test the HO2S input pump current circuit for an open or high resistance. Refer to Circuit Testing , Wiring Repairs , and Heated Oxygen Sensor Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 15  Go to Step 12 
10 Test the HO2S output pump current circuit for an open or high resistance. Refer to Circuit Testing , Wiring Repairs , and Heated Oxygen Sensor Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 15  Go to Step 12 
11 Test for intermittent and poor connections at the HO2S. Refer to Testing for Intermittent Conditions and Poor Connections , Connector Repairs , and Heated Oxygen Sensor Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 15  Go to Step 13 
12 Test for intermittent and poor connections at the engine control module (ECM). Refer to Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 15  Go to Step 14 
13 Replace the affected HO2S. 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 15  -
14 Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?
- Go to Step 15  -
15
  1. Clear the DTCs with a scan tool.
  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 2  Go to Step 16 
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 in Vehicle DTC Information System OK