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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1044 (Engine Controls Diagnosis - 6.6L (Lb7) (DTCS P0237 To P0611)) >> Diagnosis >> DTC P0238 (Federal RPO FE9, NG1) >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step number on the diagnostic table.

  1. 3:  If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records data can aid in locating an intermittent condition.
DTC P0238 (Federal RPO FE9, NG1)

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Control Module (ECM) Connector End Views  or  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 Start the engine.
Does the scan tool indicate that the boost sensor pressure is more than the specified value?		 254 kPa Go to Step 4  Go to Step 3 
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 Intermittent Conditions
4
  1. Turn OFF the ignition.
  2. Disconnect the boost sensor electrical connector. Refer to Boost Sensor Replacement (Federal Emissions) or Boost Sensor Replacement (California Emissions) .
  3. Turn the ignition ON, with the engine OFF.
Does the scan tool indicate that the boost sensor pressure is less than the specified value?		 50 kPa Go to Step 5  Go to Step 6 
5
  1. Turn OFF the ignition.
  2. Connect a jumper wire between each of the terminals in the boost sensor harness connector and the corresponding terminal at the boost sensor. Refer to Using Connector Test Adapters in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the low reference circuit of the boost sensor at the jumper wire terminal to a good ground with a DMM. Refer to Measuring Voltage Drop in Wiring Systems.
Is the voltage more than the specified value?		 0.2 V Go to Step 7  Go to Step 8 
6 Test the signal circuit of the boost sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
7 Test the low reference circuit of the boost sensor for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
8 Inspect for poor connections at the boost sensor. 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 12  Go to Step 10 
9 Inspect for poor connections at the ECM. 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 12  Go to Step 11 
10 Replace the boost sensor. Refer to Boost Sensor Replacement (Federal Emissions) or Boost Sensor Replacement (California Emissions) .
Did you complete the replacement?		 - Go to Step 12  -
11 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 12  -
12
  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 13 
13 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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