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Home >> Cadillac >> 2004 >> CTS Base, 3.2 N >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 18 (Engine Controls - 5.7L - Troubleshooting & Diagnosis) >> Troubleshooting >> Fuel Pump Electrical Circuit Diagnosis >> 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. 2:  This step verifies that the fuel pump operates.
  2. 3:  This step determines if the condition is located on the coil side or the switch side of the circuit.
  3. 7:  This step tests for a grounded voltage supply circuit.
  4. 9:  This step verifies that the fuel pump fuse is providing voltage to the fuel pump relay.
  5. 15:  This step tests for an intermittent condition between the fuse and the fuel pump.
Fuel Pump Electrical Circuit Diagnosis

Step Action Yes No
Schematic Reference:  Engine Controls Schematics 
1 Did you perform the Diagnostic System Check - Engine Controls? Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 
  1. Turn ON the ignition, with the engine OFF.
  2. Command the fuel pump relay ON and OFF with a scan tool.
Does the fuel pump turn ON and OFF?		 Go to Diagnostic Aids Go to Step 3 
3  Command the fuel pump relay ON and OFF with a scan tool.
Do you hear a click when you command the fuel pump relay ON and OFF?		 Go to Step 4  Go to Step 16 
4 Turn ON the ignition, with the engine OFF.
Does the fuel pump operate continuously?		 Go to Step 5  Go to Step 6 
5
  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 17  Go to Step 20 
6 Is the fuel pump fuse open? Go to Step 7  Go to Step 9 
7 
  1. Disconnect the fuel pump harness in-line connector located near the fuel tank. Refer to Power and Grounding Component Views in Wiring Systems.
  2. Test the supply voltage circuit of the fuel pump for a grounded circuit. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.
  3. Replace the fuel pump fuse, if necessary.
Did you find and correct the condition?		 Go to Step 21  Go to Step 8 
8
  1. Lower the fuel tank, if necessary. Refer to Fuel Tank Replacement .
  2. Test or inspect the fuel tank electrical harness for the following conditions:
  3. Replace the fuel pump fuse, if necessary.
Did you find and correct the condition?		 Go to Step 21  Go to Step 15 
9 
  1. Turn OFF the ignition.
  2. Disconnect the fuel pump relay.
  3. 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 10  Go to Step 18 
10 Connect a 15-amp fused jumper wire between the battery positive voltage circuit and the fuel pump supply circuit of the fuel pump relay.
Does the fuel pump operate?		 Go to Step 16  Go to Step 11 
11
  1. Disconnect the fuel pump harness in-line connector located near the fuel tank. Refer to Power and Grounding Component Views in Wiring Systems.
  2. Test the supply voltage circuit of the fuel pump for an open or for high resistance between the fuel pump relay and the in-line connector. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 22  Go to Step 12 
12 Test the ground circuit of the fuel pump for an open or for high resistance. Refer to Wiring Repairs and Connector Repairs in Wiring Systems
Did you find and correct the condition?		 Go to Step 22  Go to Step 13 
13 Inspect for poor connections at the fuel pump in-line connector. 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 22  Go to Step 14 
14
  1. Lower the fuel tank. Refer to Fuel Tank Replacement .
  2. Test or inspect the fuel tank electrical harness for the following conditions:
Did you find and correct the condition?		 Go to Step 22  Go to Step 20 
15 
  1. Connect all disconnected components.
  2. Install a new fuel pump fuse.
  3. Command the fuel pump ON with a scan tool.
  4. Inspect the fuel pump fuse.
Is the fuel pump fuse open?		 Go to Step 20  Go to Diagnostic Aids
16 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 22  Go to Step 21 
17 Repair the supply voltage circuit of the fuel pump for a short to voltage. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 22  -
18 Repair the battery positive voltage circuit of the fuel pump relay for an open. Refer to Wiring Repairs and Connector Repairs in Wiring Systems
Did you complete the repair?		 Go to Step 22  -
19 Test for an intermittent and for a poor connection at the fuel pump connector within the fuel tank. 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 22  Go to Step 20 
20
  1. Replace the fuel tank module. Refer to Fuel Tank Module Replacement - Primary .
  2. Replace the fuel pump fuse, if necessary.
Did you complete the replacement?		 Go to Step 22  -
21 Replace the fuel pump relay.
Did you complete the replacement?		 Go to Step 22  -
22 Operate the system in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 2 
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