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Home >> Cadillac >> 2004 >> CTS Base, 3.6 7 >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 14 (Engine Controls - 2.6L & 3.2L - Diagnosis (DTC P0449 - P2010)) >> Diagnostic Trouble Codes >> DTC P0628 >> Test Description

Test Description

WARNING: This page is about a different variant/trim than selected.

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

  1. 4:  This step verifies that the ECM is providing voltage to the fuel pump relay.
  2. 5:  This step tests for a short to ground in the control circuit to the fuel pump relay.
DTC P0628

Step Action 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
  1. Remove the rear seat cushion. Refer to Seat Cushion Replacement - Rear in Seats.
  2. Turn ON the ignition, with the engine OFF.
    3. IMPORTANT: An audible click should be heard.
  3. Command the fuel pump ON and OFF with a scan tool.
Does the fuel pump relay turn ON and OFF with each command?		 Go to Step 3  Go to Step 4 
3
  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 4  Go to Intermittent Conditions
4 
  1. Turn OFF the ignition.
  2. Disconnect the fuel pump relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the control circuit of the fuel pump relay with a test lamp connected to a good ground.
  5. Command the fuel pump ON and OFF with a scan tool.
Does the test lamp turn ON and OFF with each command?		 Go to Step 6  Go to Step 5 
5  Test the control circuit of the fuel pump relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 8  Go to Step 7 
6 Replace the fuel pump relay.
Did you complete the replacement?		 Go to Step 8  -
7 Replace the engine control module (ECM). Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 Go to Step 8  -
8
  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 9 
9 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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