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Home >> Cadillac >> 2006 >> STS Base, 3.6 7, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 3.6L - DTC P2178 To U0423 >> DTC P2636 >> Test Description
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Test Description

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

  1. 2:  This step determines if a condition current.
  2. 3:  This step verifies possible component problems within the fuel tank.
P2636 Fuel Transfer Pump Flow Insufficient

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Start the engine.
  2. Allow the engine to idle for the specified amount of time.
  3. Observed the DTC Info with a scan tool.
Does the DTC fail this ignition?		 5 minutes 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 Diagnostic Aids
4
  1. Turn ON the ignition, with the engine OFF.
  2. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
  3. Disconnect the left side fuel level sensor harness connector.
  4. Connect a 3-amp fused jumper wire between the signal circuit of the left fuel level sensor and a good ground.
  5. Monitor the Fuel Level Sensor Left Tank voltage parameter with a scan tool.
Is the voltage at the specified value?		 0.0 V Go to Step 5  Go to Step 6 
5
  1. Connect a 3-amp fused jumper wire between the signal circuit of the left fuel level sensor and the low reference circuit of the left fuel level sensor.
  2. Monitor the Fuel Level Sensor Left Tank voltage parameter with a scan tool.
Is the voltage at the specified value?		 0.0 V Go to Step 8  Go to Step 7 
6 Test the signal circuit of the left fuel level sensor for high resistance. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 13  Go to Step 10 
7 Test the low reference circuit of the left fuel level sensor for high resistance. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 13  Go to Step 10 
8
  1. Remove the fuel tank. Refer to Fuel Tank Replacement .
  2. Remove the fuel tank primary and secondary modules. Refer to Primary Fuel Tank Module Replacement and Secondary Fuel Tank Module Replacement .
  3. Inspect for the following conditions:
    • A clogged secondary fuel strainer and pick up
    • A clogged or restricted siphon jet pump
    • Broken, clogged or restricted flex tubes, primary fuel tank module
    • Broken, clogged, disconnected, or restricted fuel transfer tube inside tank
Did you find and correct the condition?		 - Go to Step 13  Go to Step 9 
9 Test for an intermittent and for a poor connection at the left fuel level sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 13  Go to Step 11 
10 Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 13  Go to Step 12 
11 Replace the left fuel level sensor. Refer to Secondary Fuel Tank Module Replacement .
Did you complete the replacement?		 - Go to Step 13  -
12 Replace the ECM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 13  -
13
  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 14 
14 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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