Fuel Pump Circuit Troubleshooting (2016-18)

If you suspect a problem with the fuel pump, check that the fuel pump actually runs; when it is on, you will hear some noise if you listen to the fuel fill port with the fuel fill cap removed. The fuel pump should run for 2 seconds when the engine start/stop button is pressed to select the ON mode. If the fuel pump does not make noise, check as follows:

1. Under-dash fuse/relay box internal circuit check:

   Press the engine start/stop button to select the OFF mode.

   - 2. Remove PGM-FI main relay 2 (A) from the under-dash fuse/relay box.

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   - 3. Press the engine start/stop button to select the ON mode.

   - 4. Measure the voltage between test points 1 and 2.

   Test condition	ON mode
   	PGM-FI main relay 2: disconnected
   Test point 1	PGM-FI main relay 2 4P socket No. 3
   Test point 2	Body ground

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   Is there battery voltage?

   YES 

   Go to step 2.

   NO 

   • Test PGM-FI main relay 1 . If the relay is OK, replace the under-dash fuse/relay box.
   • Replace PGM-FI main relay 1.
2. Open wire check (IG1 FUEL PUMP line):

   Measure the voltage between test points 1 and 2.

   Test condition	ON mode
   	PGM-FI main relay 2: disconnected
   Test point 1	PGM-FI main relay 2 4P socket No. 2
   Test point 2	Body ground

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   Is there battery voltage?

   YES 

   Go to step 3.

   NO 

   • Check the No. B4 (15 A) fuse in the under-dash fuse/relay box.
   • If needed, replace the under-dash fuse/relay box .
3. Open wire check (FUEL PUMP RLY CL- line):

   Press the engine start/stop button to select the OFF mode.

   - 2. Jump the SCS line with the HDS, and wait more than 1 minute.

   SCS Short

   - 3. Disconnect the following connector.

   PCM connector A (51P)

   - 4. Connect terminals A and B with a jumper wire.

   Terminal A	PGM-FI main relay 2 4P socket No. 4
   Terminal B	Body ground

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   - 5. Check for continuity between test points 1 and 2.

   Test condition	OFF mode
   	PGM-FI main relay 2: disconnected
   	PGM-FI main relay 2 4P socket No. 4: jumped to body ground
   	PCM connector A (51P): disconnected

   Test point 1	PCM connector A (51P) No. 8
   Test point 2	Body ground

   Is there continuity?

   YES 

   The FUEL PUMP RLY CL- wire is OK. Go to step 4.

   NO 

   Repair an open in the FUEL PUMP RLY CL- wire between PGM-FI main relay 2 and the PCM (A8).

4. Determine possible failure area (PGM-FI main relay 2, others):

   Remove the jumper wire from the PGM-FI main relay 2 4P socket.

   - 2. Reinstall PGM-FI main relay 2.

   - 3. Connect terminals A and B with a jumper wire.

   Terminal A	PCM connector A (51P) No. 7
   Terminal B	Body ground

   - 4. Press the engine start/stop button to select the ON mode.

   - 5. Measure the voltage between test points 1 and 2.

   Test condition	ON mode
   	PCM connector A (51P): disconnected
   	PCM connector A (51P) No. 7: jumped to body ground
   Test point 1	PCM connector A (51P) No. 8
   Test point 2	Body ground

   Is there battery voltage?

   YES 

   Go to step 5.

   NO 

   Replace PGM-FI main relay 2.

5. PCM operation check:

   Press the engine start/stop button to select the OFF mode.

   - 2. Remove the jumper wire from PCM connector A (51P).

   - 3. Reconnect PCM connector A (51P).

   - 4. Exit the SCS mode with the HDS.

   SCS Open

   - 5. Press the engine start/stop button to select the ON mode, then measure the voltage between test points 1 and 2.

   Test condition	Within 2 seconds after selecting the ON mode
   Test point 1	Under-dash fuse/relay box connector C (38P) No. 35
   Test point 2	Body ground

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   Is there battery voltage?

   YES 

   Update the PCM if it does not have the latest software or substitute a known-good PCM , then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM .

   NO 

   Go to step 6.

6. Determine possible failure area (FUEL PUMP RLY OUT line, GND line):

   Press the engine start/stop button to select the OFF mode.

   - 2. Remove the access panel from the floor .

   - 3. Disconnect the following connector.

   Fuel tank unit 4P connector

   - 4. Press the engine start/stop button to select the ON mode, then measure the voltage between test points 1 and 2.

   Test condition	Within 2 seconds after selecting the ON mode
   	Fuel tank unit 4P connector: disconnected
   Test point 1	Fuel tank unit 4P connector No. 1
   Test point 2	Body ground

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   Is there battery voltage?

   YES 

   Go to step 9.

   NO 

   Go to step 7.

7. Open wire check (FUEL PUMP RLY OUT line) 1:

   Press the engine start/stop button to select the OFF mode.

   - 2. Remove PGM-FI main relay 2 (A) from the under-dash fuse/relay box.

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   - 3. Connect terminals A and B with a jumper wire.

   Terminal A	PGM-FI main relay 2 4P socket No. 1
   Terminal B	PGM-FI main relay 2 4P socket No. 2

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   - 4. Press the engine start/stop button to select the ON mode.

   - 5. Measure the voltage between test points 1 and 2.

   Test condition	ON mode
   	Fuel tank unit 4P connector: disconnected
   	PGM-FI main relay 2 :disconnected
   	PGM-FI main relay 2 4P socket No. 1 and No. 2: jumped
   Test point 1	Fuel tank unit 4P connector No. 1
   Test point 2	Body ground

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   Is there battery voltage?

   YES 

   The FUEL PUMP RLY OUT wire is OK. Replace PGM-FI main relay 2.

   NO 

   Go to step 8.

8. Open wire check (FUEL PUMP RLY OUT line) 2:

   Measure the voltage between test points 1 and 2.

   Test condition	ON mode
   	Fuel tank unit 4P connector: disconnected
   	PGM-FI main relay 2 :disconnected
   	PGM-FI main relay 2 4P socket No. 1 and No. 2: jumped
   Test point 1	Under-dash fuse/relay box connector B (44P) No. 6
   Test point 2	Body ground

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   Is there battery voltage?

   YES 

   Repair an open in the FUEL PUMP RLY OUT wire between the under-dash fuse/relay box and the fuel tank unit.

   NO 

   The FUEL PUMP RLY OUT wire is OK. Replace the under-dash fuse/relay box .

9. Open wire check (GND line):

   Press the engine start/stop button to select the OFF mode.

   - 2. Check for continuity between test points 1 and 2.

   Test condition	OFF mode
   	Fuel tank unit 4P connector: disconnected
   Test point 1	Fuel tank unit 4P connector No. 3
   Test point 2	Body ground

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   Is there continuity?

   YES 

   The GND wire is OK. Replace the fuel pump .

   NO 

   Repair an open in the GND wire between the fuel tank unit and G601.