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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Vivant 🢒 Engine 🢒 Engine Controls - 2.0L (L34 GMDAT) 🢒 Fuel Pump Electrical Circuit Diagnosis

Fuel Pump Electrical Circuit Diagnosis Non European Emissions

Circuit Description

When the ignition switch is turned ON, the electronic control module (ECM) will activate the fuel pump relay and run the in-tank fuel pump. The fuel pump will operate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.

If there are no reference pulses, the ECM will shut OFF the fuel pump within 2 seconds after the ignition switch is turned ON.

Diagnostic Aids

An intermittent problem may be caused by a poor connection, rubbed through wire insulation, or a broken wire inside the insulation.

Step

Action

Values

Yes

No

1
  1. Turn the ignition to LOCK for 10 seconds.
  2. Turn ON the ignition.
  3. Listen for in-tank fuel pump operation.

Does the fuel pump operate for the time specified?

2 seconds

System OK

Go to Step 2

2
  1. Turn the ignition to LOCK.
  2. Disconnect the fuel pump relay.
  3. Connect a test light between the fuel pump relay connector terminal 85 and ground.
  4. Turn ON the ignition.

Is the test light ON?

--

Go to Step 3

Go to Step 8

3
  1. Turn the ignition to LOCK.
  2. Connect a test light between the fuel pump relay connector terminal 86 and battery positive.
  3. Turn ON the ignition.
  4. With the ignition ON, the test light should light for the time specified.

Is the test light ON?

2 seconds

Go to Step 4

Go to Step 9

4
  1. Turn the ignition to LOCK.
  2. Connect a test light between the fuel pump relay connector terminal 30 and ground.

Is the test light ON?

--

Go to Step 5

Go to Step 11

5

Inspect for an open or short to ground in the wire between the fuel pump relay connector terminal 87 and the fuel pump connector terminal 3.

Is the condition found?

--

Go to Step 6

Go to Step 7

6
  1. Repair the wire between the fuel pump relay connector terminal 87 and the fuel pump connector terminal 3.
  2. Install the fuel pump relay.
  3. Turn the ignition to LOCK for 10 seconds.
  4. Turn ON the ignition.

Does the fuel pump operate for the time specified?

2 seconds

System OK

--

7
  1. Replace the fuel pump relay.
  2. Turn the ignition to LOCK for 10 seconds.
  3. Turn ON the ignition.

Does the fuel pump operate for the time specified?

2 seconds

System OK

--

8
  1. Inspect the engine fuse block fuse EF23, EF25 LHD, or instrument panel (I/P) fuse F13 RHD.
  2. Inspect for an open wire between the fuel pump relay connector terminal 85 and the main relay connector terminal 87.

Is the condition found?

--

Go to Step 13

Go to Main Relay Circuit Diagnosis

9

Inspect for an open wire between the fuel pump relay connector terminal 86 to the ECM connector terminal A12.

Is the condition found?

--

Go to Step 10

Go to Step 12

10
  1. Repair the wire between the fuel pump relay connector terminal 86 to the ECM connector terminal A12.
  2. Install the fuel pump relay.
  3. Turn the ignition to LOCK for 10 seconds.
  4. Turn ON the ignition.

Does the fuel pump operate for the time specified?

2 seconds

System OK

--

11
  1. Repair the wire between the fuel pump relay connector terminal 30 and the battery.
  2. Install the fuel pump relay.
  3. Turn the ignition to LOCK for 10 seconds.
  4. Turn ON the ignition.

Does the fuel pump operate for the time specified?

2 seconds

System OK

--

12
  1. Replace the electronic control module.
  2. Turn the ignition to LOCK for 10 seconds.
  3. Turn ON the ignition.

Does the fuel pump operate for the time specified?

2 seconds

System OK

--

13

Replace the fuse or repair the wire as needed.

Did you complete the repair?

2 seconds

System OK

--

Fuel Pump Electrical Circuit Diagnosis European Emissions

Circuit Description

When the ignition switch is turned ON, the engine control module (ECM) will supply battery voltage to activate the fuel pump relay and run the in-tank fuel pump. The fuel pump will operate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.

If there are no reference pulses, the ECM will shut OFF the fuel pump within 2 seconds after the ignition switch is turned ON.

Diagnostic Aids

An intermittent condition may be caused by a poor connection, rubbed through wire insulation, or a broken wire inside the insulation.

Step

Action

Values

Yes

No

1
  1. Turn OFF the ignition for 10 seconds.
  2. Turn ON the ignition.
  3. Listen for in-tank fuel pump operation.

Does the fuel pump operate for the time specified?

2 seconds

System OK

Go to Step 2

2
  1. Turn OFF the ignition.
  2. Connect battery positive to the fuel pump test connect.
  3. Listen for in-tank fuel pump operation.

Does the fuel pump operate?

--

Go to Step 4

Go to Step 3

3

  1. Inspect for an open circuit between the fuel pump test connector and ground G301, and repair as needed.
  2. Inspect the fuel cut-off switch and reset or replace the fuel cut-off switch.

Did you complete the repair?

--

System OK

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Disconnect the fuel pump.
  3. Connect a test light between the fuel pump relay connector terminal 85 and battery positive.

Is the test light ON?

--

Go to Step 6

Go to Step 5

5

Inspect for an open circuit between terminal 85 of the fuel pump relay and ground G102, and repair as needed.

Did you complete the repair?

--

System OK

--

6
  1. Turn OFF the ignition.
  2. Connect a test light between the fuel pump relay connector terminal 86 and ground.
  3. Turn ON the ignition.

Is the test light ON for the time specified?

2 seconds

Go to Step 8

Go to Step 7

7

Inspect for an open circuit between terminal 86 of the fuel pump relay and terminal K54 of the ECM, and repair as needed.

Did you complete the repair?

--

System OK

--

8
  1. Turn OFF the ignition.
  2. Connect a test light between the fuel pump relay connector terminal 30 and ground.

Is the test light ON?

--

Go to Step 10

Go to Step 9

9

  1. Inspect the fuse EF23. If open, repair the short circuit between the fuel pump relay 30 terminal.
  2. Replace the fuse as needed.
  3. Repair an open circuit as needed.

Did you complete the repair?

--

System OK

--

10
  1. Turn OFF the ignition.
  2. Measure the resistance between the following terminals:
    3. • Terminal 87 of the fuel pump relay and terminal M3 of the ECM
    • Terminal 87 of the fuel pump relay and terminal 1 of the fuel cut-off switch, or terminal 2 of connector C215

Does the resistance measured equal the specified value?

0 ohms

Go to Step 12

Go to Step 11

11

Repair the open circuit as needed.

Did you complete the repair?

--

System OK

--

12

Replace the fuel pump relay.

Is the replacement complete?

--

System OK

Go to Step 13

13

Replace the ECM. Refer to Engine Control Module Description .

Is the replacement complete?

--

System OK

--