05245 05DK00 FUEL PUMP CONTROL CIRCUIT CIRCUIT DESCRIPTION In the diagram below, when the engine is cranked, current flows from terminal ST2 of the ignition switch to the starter relay coil and also current flows to terminal STA of the ECM (STA signal). When the STA signal and NE signal are input to the ECM, Tr is turned ON, current flows to the coil of the circuit opening relay, the relay switches on, power is supplied to the fuel pump and the fuel pump operates. While the NE signal is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON) and the fuel pump also keeps operating. EFI Circuit Opening Fuel Pump AM2 IG2 ST2 ECM AM2 EFI Ignition SW ST Park / Neutral Start Switch (A/T) or Clutch Start Switch (M/T) FC Tr STA MAIN ST (NE Signal) NE Starter Battery A8226 405
05246 WIRI DIAGRAM I0 Ignition Switch 5 6 AM2 IG2 WR B O 6 O 7 2 A 3 A WR BR BY BY A Instrument Panel J/B 2 2 AM2 EFI EFI 5 3 2 3 5 2 Circuit Opening 3 BL MAIN Engine Room R/B F8 Fusible Limk Block WB BY 4 BR F4 Fuel Pump 6 T 9 BR H N3 Noise Filter (Fuel Pump) GR 5 BR 0 7 E5 FC E0 ECM WB Battery EB BJ ED A83830 406
INSPECTION PROCEDURE Handheld tester: PERFORM ACTIVE TEST BY HANDHELD TESTER(OPERATION OF CIRCUIT OPENI RELAY) 05247 Connect the handheld tester to the DLC3. Turn the ignition switch ON and push the handheld tester main switch ON. Select the item DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / FUEL PUMP / SPD. Check the relay operation while operating it with the handheld tester. Standard: Operating noise can be heard from the relay. Go to step 7 2 CHECK ECM POWER SOURCE CIRCUIT (See page 05239) 3 INSPECT CIRCUIT OPENI RELAY REPAIR OR REPLACE POWER SOURCE CIRCUIT B6200 Inspect the circuit opening relay. Standard: 2 Below Ω 0 kω or higher 3 5 Below Ω (Apply battery voltage to terminals and 2) REPLACE CIRCUIT OPENI RELAY 407
05248 4 INSPECT ECM(FC VOLTAGE) E5 Turn the ignition switch ON. Measure the voltage between the specified terminals of the and E5 ECM Standard: FC (0) E0 (E57) 9 to 4 V E0 () FC (+) A8294 REPLACE ECM 5 CHECK HARNESS AND (EFI RELAY CIRCUIT OPENI RELAY) Engine Room R/B Remove the EFI relay from the engine room R/B. EFI A72874 EFI relay (3) Circuit opening relay () EFI relay (3) Circuit opening relay (5) Below Ω EFI relay (3) or Circuit opening relay () Body ground EFI relay (3) or Circuit opening relay (5) Body ground Reinstall the EFI relay. 0 kω or higher REPAIR OR REPLACE HARNESS OR 408
05249 6 CHECK HARNESS AND (ECM CIRUIT OPENI RELAY) Disconnect the ECM connector. FC A65748 FC (0) Circuit opening relay (2) Below Ω FC (0) Circuit opening relay (2) Body ground Reconnect the ECM connector. 0 kω or higher REPAIR OR REPLACE HARNESS OR REPLACE ECM (See page 07) 7 INSPECT FUEL PUMP ASSY (See page 7) REPAIR OR REPLACE FUEL PUMP ASSY 409
05250 8 CHECK HARNESS AND (CIRCUIT OPENI RELAY FUEL PUMP, FUEL PUMP BODY GROUND) Wire Harness Side Fuel Pump Connector F4 Disconnect the F4 fuel pump connector. Circuit opening relay (3) Fuel pump (F44) Fuel pump (F45) Body ground Circuit opening relay (3) or Fuel pump (F44) Body ground Reconnect the fuel pump connector. Continuity 0 kω or higher Front View A66276 REPAIR OR REPLACE HARNESS OR REPLACE ECM (See page 07) OBD II scan tool (excluding handheld tester): CHECK OPERATION OF FUEL PUMP E5 E0 () FC (+) A8294 Turn the ignition switch ON. Connect between terminals FC and E0 of the ECM connector. Check for fuel pressure in the fuel inlet hose when it is pinched off. Result: There is pressure in fuel inlet hose. HINT: At this time, you will hear the fuel flowing sound. A72879 40
0525 PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE (See page 0542) 2 CHECK ECM POWER SOURCE CIRCUIT (See page 05239) 3 INSPECT CIRCUIT OPENI RELAY REPAIR OR REPLACE POWER SOURCE CIRCUIT B6200 Inspect the circuit opening relay. Standard: 2 Below Ω 0 kω or higher 3 5 Below Ω (Apply battery voltage to terminals and 2) REPLACE CIRCUIT OPENI RELAY 4 INSPECT ECM(FC VOLTAGE) E5 Turn the ignition switch ON. Measure the voltage between the specified terminals of the and E5 ECM Standard: FC (0) E0 (E57) 9 to 4 V E0 () FC (+) A8294 Go to step 7 4
05252 5 CHECK HARNESS AND (EFI RELAY CIRCUIT OPENI RELAY) Engine Room R/B Remove the EFI relay from the engine room R/B. EFI A72874 EFI relay (3) Circuit opening relay () EFI relay (3) Circuit opening relay (5) Below Ω EFI relay (3) or Circuit opening relay () Body ground EFI relay (3) or Circuit opening relay (5) Body ground Reinstall the EFI relay. 0 kω or higher REPAIR OR REPLACE HARNESS OR 6 CHECK HARNESS AND (ECM CIRCUIT OPENI RELAY) Disconnect the ECM connector. FC A65748 FC (0) Circuit opening relay (2) Below Ω FC (0) Circuit opening relay (2) Body ground Reconnect the ECM connector. 0 kω or higher REPAIR OR REPLACE HARNESS OR REPLACE ECM (See page 07) 42
05253 7 INSPECT FUEL PUMP ASSY (See page 7) REPAIR OR REPLACE FUEL PUMP ASSY 8 CHECK HARNESS AND (CIRCUIT OPENI RELAY FUEL PUMP, FUEL PUMP BODY GROUND) Wire Harness Side Fuel Pump Connector F4 Disconnect the F4 fuel pump connector. Circuit opening relay (3) Fuel pump (F44) Fuel pump (F45) Body ground Circuit opening relay (3) or Fuel pump (F44) Body ground Reconnect the fuel pump connector. Continuity 0 kω or higher Front View A66276 REPAIR OR REPLACE HARNESS OR REPLACE ECM (See page 07) 43