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HOMESERVICE MANUALSCHEVROLET2006CHEVY EXPRESS G2500, VAN CARGO, 6.6 2REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 962 (ENGINE CONTROL SYSTEM & FUEL SYSTEM - 4.3L - DTC P0507 TO DTC P2A04)DTC P0641TEST DESCRIPTION
2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2

Test Description

2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2SECTION Test Description
WARNING: This page is about a different car, the 2007 GMC Savana and 2007 Chevrolet Chevy Express. 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. 8:  A short to voltage on the signal circuit of the MAP sensor will backfeed through the sensor into the 5-volt reference circuit and set this DTC.
DTC P0641

Step Action Values Yes No
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2
  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 3  Go to Testing for Intermittent Conditions and Poor Connections
3
  1. Turn OFF the ignition.
  2. Disconnect the engine oil pressure (EOP) sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the 5-volt reference circuit of the EOP sensor to a good ground with a DMM. Refer to Circuit Testing .
Is the voltage within the specified range?		 4.8-5.2 V Go to Step 4  Go to Step 5 
4
  1. Connect the EOP sensor.
  2. Disconnect the manifold absolute pressure (MAP) sensor.
  3. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM. Refer to Circuit Testing .
Is the voltage within the specified range?		 4.8-5.2 V Go to Testing for Intermittent Conditions and Poor Connections Go to Step 10 
5 Is the voltage measured in Step 3 more than the specified value? 5.2 V Go to Step 8  Go to Step 6 
6
  1. Monitor the DMM while disconnecting all other devices connected to the 5-volt reference circuit, one at a time. Refer to Engine Controls Component Views .
  2. If the voltage changes when one of the devices are disconnected, replace the component. Refer to appropriate replacement procedure below:
Was a component replaced?		 - Go to Step 12  Go to Step 7 
7 Test all 5-volt reference circuits for a short to ground or any sensor low reference circuit. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 12  Go to Step 11 
8  Test the MAP sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
9 Test all 5-volt reference circuits for a short to voltage. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 12  Go to Step 11 
10 Replace the EOP sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement .
Did you complete the replacement?		 - Go to Step 12  -
11 Replace the powertrain control module (PCM). Refer to Control Module References for replacement, setup, and programming.
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 - Vehicle System OK
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.