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Test Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 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. 2:  Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3:  This step determines if the condition is located on the coil side or the switch side of the circuit.
  3. 4:  This step verifies that the PCM is providing voltage to the fuel pump relay.
  4. 5:  This step tests for an open in the fuel pump relay ground circuit.
  5. 6:  This step determines if a voltage is constantly being applied to the fuel pump relay.
  6. 12:  This tests for a grounded fuel pump supply voltage circuit. The fuel pump fuse supplies power to fuel pump. Disconnecting the fuel pump in-line harness connector isolates the fuel pump supply voltage circuit.
  7. 15:  This step jumps the fuel pump relay in order to activate the fuel pump.
  8. 16:  This step tests for an open in the fuel pump feed circuit between the in-line connector and the fuel pump relay.
  9. 17:  This step tests for an open or high resistance in the fuel pump ground circuit.
  10. 20:  This step determines if the condition with the circuit is intermittent. If the fuse does not open, inspect the supply voltage circuit between the fuse and the fuel pump for an intermittent condition.
Fuel Pump Electrical Circuit Diagnosis

Step Action Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Controls Connector End Views  or  Powertrain Control Module (PCM) 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. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the fuel pump relay ON and OFF.
Does the fuel pump turn ON and OFF?		 Go to Intermittent Conditions  Go to Step 3 
3  With a scan tool, command the fuel pump relay ON and OFF.
Do you hear a click when you command the fuel pump relay ON and OFF?		 Go to Step 9  Go to Step 4 
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 that is connected to a good ground.
  5. With a scan tool, command the fuel pump ON and OFF.
Does the test lamp turn ON and OFF?		 Go to Step 5  Go to Step 6 
5 
  1. Connect the test lamp between the control circuit of the fuel pump relay and the ground circuit of the fuel pump relay.
  2. With a scan tool, command the fuel pump ON and OFF.
Does the test lamp turn ON and OFF?		 Go to Step 21  Go to Step 24 
6  Does the test lamp remain illuminated with each command? Go to Step 7  Go to Step 8 
7 Test the control circuit of the fuel pump relay 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 29  Go to Step 28 
8 Test the control circuit of the fuel pump relay for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 29  Go to Step 22 
9 Turn ON the ignition, with the engine OFF.
Does the fuel pump operate continuously?		 Go to Step 10  Go to Step 11 
10
  1. Turn OFF the ignition.
  2. Disconnect the fuel pump relay.
  3. Turn ON the ignition, with the engine OFF.
Does the fuel pump operate continuously?		 Go to Step 23  Go to Step 27 
11 Is the fuel pump fuse open? Go to Step 12  Go to Step 14 
12 
  1. Disconnect the fuel pump harness in-line connector located near the fuel tank.
  2. Test the fuel pump supply voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  3. Replace the fuel pump fuse if necessary.
Did you find and correct the condition?		 Go to Step 29  Go to Step 13 
13
  1. Lower the fuel tank if necessary. Refer to Fuel Tank Replacement (Prior to VIN 4S558922 (100mm Sender)) or Fuel Tank Replacement (VIN 4S558922 and Later (130mm Sender)) .
  2. Test or inspect the fuel tank electrical harness for the following:
  3. Replace the fuel pump fuse if necessary.
Did you find and correct the condition?		 Go to Step 29  Go to Step 20 
14
  1. Turn OFF the ignition.
  2. Disconnect the fuel pump relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the battery positive voltage circuit of the fuel pump relay with a test lamp connected to a good ground.
Does the test lamp illuminate?		 Go to Step 15  Go to Step 25 
15  Connect a 10-amp fused jumper wire between the battery positive voltage circuit and the fuel pump supply voltage circuit in the fuel pump cavity.
Does the fuel pump operate?		 Go to Step 21  Go to Step 16 
16 
  1. Disconnect the fuel pump harness in-line connector located near the fuel tank.
  2. Test the fuel pump supply voltage circuit for an open or high resistance between the fuel pump relay and the in-line connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 29  Go to Step 17 
17 
IMPORTANT: Inspect the ground circuit for being tight, corrosion on the terminals, or damage to the wiring harness.
Test the ground circuit of the fuel pump for an open or high resistance between the body pass through connector and the ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 Go to Step 29  Go to Step 18 
18 Inspect for poor connections at the fuel pump in-line connector to the body pass through connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems.
Did you find and correct the condition?		 Go to Step 29  Go to Step 19 
19
  1. Lower the fuel tank. Refer to Fuel Tank Replacement (Prior to VIN 4S558922 (100mm Sender)) or Fuel Tank Replacement (VIN 4S558922 and Later (130mm Sender)) .
  2. Test or inspect the fuel tank electrical harness for the following:
Did you find and correct the condition?		 Go to Step 29  Go to Step 26 
20 
  1. Connect all disconnected components.
  2. Install a new fuel pump fuse.
  3. With a scan tool, command the fuel pump ON.
Is the fuel pump fuse open?		 Go to Step 26  Go to Intermittent Conditions 
21 Inspect 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 29  Go to Step 27 
22 Inspect for poor connections at the harness of the PCM. 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 29  Go to Step 28 
23 Repair the fuel pump supply voltage circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 29  -
24 Repair the fuel pump relay ground circuit for an open ground. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 29  -
25 Repair the battery positive voltage circuit of the fuel pump relay for an open. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 29  -
26
IMPORTANT: Inspect for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump.
  1. Replace the fuel pump. Refer to Fuel Sender Assembly Replacement (Prior to VIN 4S558922 (100mm Sender)) or Fuel Sender Assembly Replacement (VIN 4S558922 and Later (130mm Sender)) .
  2. Replace the fuel pump fuse, if necessary.
Did you complete the replacement?		 Go to Step 29  -
27
IMPORTANT: Before replacing the fuel pump relay, inspect the fuel pump prime circuit for a short to voltage.
Replace the fuel pump relay.Did you complete the replacement?		 Go to Step 29  -
28 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 Go to Step 29  -
29 Operate the system in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 2 
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