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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1163 (Engine Controls Diagnosis - 3.6L (Ly7) (DTC P0442 - DTC P167A)) >> Diagnostic Trouble Codes >> DTC P0629 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 4:  This step verifies that the control module is providing voltage to the fuel pump relay.
  2. 5:  This step tests for an open in the ground circuit to the fuel pump relay.
DTC P0629 Fuel Pump Relay Control Circuit High Voltage

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
IMPORTANT: Additional DTCs may set when using the Fuel Pump output control.
  1. Turn ON the ignition, with the engine OFF.
  2. 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. 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 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 when commanded?		 Go to Step 5  Go to Step 6 
5 
  1. Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the fuel pump relay.
  2. Command the fuel pump ON and OFF with a scan tool.
Does the test lamp turn ON and OFF when commanded?		 Go to Step 7  Go to Step 9 
6 Test the control circuit of the fuel pump relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs Circuit in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 8 
7 Test for shorted terminals and for poor connections at the fuel pump relay. 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 
8 Test for shorted terminals and for poor connections at the engine control module (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 
9 Repair the open ground circuit of the fuel pump relay. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 12  -
10 Replace the fuel pump relay.
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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