Fuel Pump Relay: Testing and Inspection

Fuel Pump Relay (Circuit Open Relay):

Perform tests in the order listed.

TEST 1 - RELAY SWITCHING FUNCTION CHECK

1. Disconnect relay from its harness connector.

2. Apply 12 volts and ground to the relay terminals listed below and check for the correct result.

12V/Grnd - CORRECT RESULT
"STA"/"E1" - Energizes relay, connects terminals "B" and "Fp" (continuity).
"B"/"Fp" - Energizes relay, 12 volts becomes available at terminal Fp.

If results are not correct as described, replace relay.

TEST 2 - RELAY RESISTANCE CHECK

Check resistance between the following relay terminals.

"STA"/"E1" - Resistance...21 - 43 ohms
"B"/"Fc" - Resistance...109 - 226 ohms
"B"/"Fp" - Resistance...infinite (no continuity)

If results are not correct as described, replace relay.

TEST 3 - RELAY CIRCUIT (WIRING) CHECK

Check voltage at the following terminals with the relay installed, under the conditions listed below.

3A - IGNITION "OFF"
No voltage at any terminal.

3B - IGNITION "ON" ENGINE NOT RUNNING

Terminal "STA" - 0 volts
Terminal "B" - 12 volts
Terminal "Fp" - 0 volts
Terminal "Fc" - 12 volts


3C - IGNITION IN "START" POSITION (CRANKING)

Terminal "STA" - 12 volts
Terminal "B" - 12 volts
Terminal "Fp" - 12 volts
Terminal "Fc" - 0 volts (or nearly zero)

3D - IGNITION "ON" ENGINE RUNNING

Terminal "STA" - 0 volts
Terminal "B" - 12 volts
Terminal "Fp" - 12 volts
Terminal "Fc" - 0 volts (or nearly zero)

NOTE: Relay terminal "E1" is a ground.

If voltage at any terminal is not correct, check the wiring associated with that terminal.

If 12 volts is present at terminal "Fc" during engine cranking or engine running, and the engine dies after starting, check for open in wiring between that terminal and ECU terminal "1i". If wiring is OK, ECU is not receiving a "crank signal" or "engine run signal" or ECU is defective.