Circuit Description
The secondary fuel pump is located in the rear fuel tank. The secondary fuel pump is powered by a secondary fuel pump relay. Fuel is transferred from the rear fuel tank to the front fuel tank in order to ensure all of the usable fuel volume is available to the primary fuel pump. The secondary fuel pump relay supply voltage is received from the primary fuel pump relay when the primary fuel pump is energized. This diagnostic trouble code (DTC) sets when the powertrain control module (PCM) commands the secondary fuel pump ON and a predetermined change in both the front and rear fuel level sensors does not occur.
Conditions for Running the DTC
| • | DTCs P0461, P0462, P0463, P1431, P1432, or P1433 are not set. |
| • | The engine is running. |
| • | The vehicle speed is 0 km/h (0 mph). |
| • | The primary fuel level is less than 25 L (6.6 gal). |
| • | The secondary fuel level is between 3-10 L (0.79-2.6 gal). |
| • | The above conditions are met for 20 seconds before the secondary pump is commanded ON. |
| • | The secondary fuel pump is commanded ON for 120 seconds. |
Conditions for Setting the DTC
The PCM does not detect a change of 4 L (1.06 gal) in both the primary and secondary fuel level sensors with the secondary pump commanded ON for 120 seconds.
Action Taken When the DTC Sets
| • | The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
Conditions for Clearing the DTC
| • | A last test failed, or current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Use a scan tool in order to clear the DTC. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests the supply voltage circuit of the secondary fuel pump relay. The test lamp should illuminate as the primary fuel pump is commanded ON.
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This step verifies the secondary fuel pump operation. Listen for an audible sound as the secondary fuel pump relay harness connector is jumpered.
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This step verifies that there is adequate fuel in the rear fuel tank. The rear fuel tank sensor voltage must be above 1 volt in order to continue.
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This step tests the secondary fuel pumps ability to transfer fuel. The rear fuel level sensor voltage should decrease while the secondary fuel pump is ON.
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This step tests for a short to ground on the control circuit of the secondary fuel pump relay. If the test lamp illuminates, a short to ground is indicated.
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This step tests for a short to voltage on the control circuit of the secondary fuel pump relay. If the test lamp illuminates, a short to voltage is indicated.
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This step verifies the secondary fuel pump relay operation. An audible click should be heard as the secondary fuel pump relay control circuit is grounded. The secondary fuel pump should turn ON as the fuel pump relay control circuit is grounded.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||
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Important: The fuel level must be between 25 percent and 50 percent to perform this diagnostic procedure. If the fuel level is not within this range, misdiagnosis will occur.
Does the test lamp illuminate when the fuel pump is commanded ON? | -- | Go to Step 3 | Go to Step 22 | |||||
3 | Probe the ignition 1 voltage circuit of the secondary fuel pump relay, switch side, with a test lamp connected to a good ground. Is the test lamp illuminated? | -- | Go to Step 4 | Go to Step 12 | ||||
Jumper the ignition 1 voltage circuit to the secondary fuel pump supply voltage circuit, at the secondary fuel pump relay harness connector. Does the secondary fuel pump turn ON? | -- | Go to Step 5 | Go to Step 16 | |||||
Is the rear fuel level sensor voltage above the specified value? | 1 V | Go to Step 7 | Go to Step 6 | |||||
6 | Add the specified amount of fuel to the fuel tank. Did you complete the action? | 19 L (5 gal) | Go to Step 7 | -- | ||||
Does the rear fuel level sensor voltage decrease as the secondary fuel pump is operating? | -- | Go to Step 8 | Go to Step 18 | |||||
Does the test lamp illuminate? | -- | Go to Step 23 | Go to Step 9 | |||||
Probe the secondary fuel pump relay control circuit with a test lamp connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 27 | Go to Step 10 | |||||
Does the secondary fuel pump turn ON when the fuel pump relay control terminal is grounded? | -- | Go to Step 11 | Go to Step 19 | |||||
11 | Test the secondary fuel pump relay control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 21 | ||||
12 | Inspect the ENG 1 fuse. Is the ENG 1 fuse open? | -- | Go to Step 13 | Go to Step 25 | ||||
13 | Test the ignition 1 voltage circuit of the secondary 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 31 | Go to Step 14 | ||||
14 | Test the voltage supply circuit of the secondary fuel pump 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 31 | Go to Step 15 | ||||
15 |
Is the fuse open? | -- | Go to Step 29 | Go to Intermittent Conditions | ||||
16 |
Is the test lamp illuminated? | -- | Go to Step 17 | Go to Step 26 | ||||
17 | Probe the ground circuit of the secondary fuel pump with a test lamp connected to B+. Does the test lamp illuminate? | -- | Go to Step 20 | Go to Step 24 | ||||
18 | Inspect the fuel line between the primary and secondary fuel tanks for a restriction. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 29 | ||||
19 | Inspect for poor connections at the harness connector of the secondary 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 31 | Go to Step 28 | ||||
20 | Inspect for poor connections at the harness connector of the secondary fuel pump. 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 31 | Go to Step 29 | ||||
21 | Inspect for poor connections at the harness connector 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 31 | Go to Step 30 | ||||
22 | Repair the open supply voltage circuit of the secondary fuel pump relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 31 | -- | ||||
23 | Repair the short to ground in the control circuit of the secondary fuel pump relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 31 | -- | ||||
24 | Repair the open ground circuit of the secondary fuel pump. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 31 | -- | ||||
25 | Repair the open ignition voltage circuit of the secondary fuel pump relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 31 | -- | ||||
26 | Repair the open supply voltage circuit of the secondary fuel pump. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 31 | -- | ||||
27 | Repair the short to voltage on the control circuit of the secondary fuel pump relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 31 | -- | ||||
28 | Replace the secondary fuel pump relay. Did you complete the replacement? | -- | Go to Step 31 | -- | ||||
29 | Replace the rear fuel level sensor assembly. Refer to Fuel Level Sensor Replacement . Did you complete the replacement? | -- | Go to Step 31 | -- | ||||
30 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 31 | -- | ||||
31 |
Does the DTC run and pass? | -- | Go to Step 32 | Go to Step 2 | ||||
32 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||
