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DTC P020:

Fuel Pump Circuit:

CIRCUIT DESCRIPTION:
The fuel pump receives power from CKT 120 through either fuel pump 1 or 2 relay. The PCM energizes the fuel pump 1 relay for 2 seconds at key "ON" to provide fuel pressure for starting. After the 2 second fuel pump prime, the PCM will not power the fuel pump 1 relay until 4X reference pulses are received indicating that the engine is turning (crank or run). The oil pressure sensor is provided as a "backup" to the fuel pump 1 relay. A vehicle with fuel pump 1 relay inoperative will crank until oil pressure builds (oil telltale off) then start and run as the switch inside the oil pressure sensor closes energizing fuel pump 2 relay providing power to the fuel pump. The PCM monitors voltage on the fuel pump power CKT 120 to detect fuel pump voltage supply faults. Code P020 is set when the PCM sees the fuel pump not energized (2 volts or less on the feedback) with the engine cranking or running. Since the switch inside the oil pressure sensor closes when oil pressure increases after crank, this code will most likely set only during crank.

TEST CONDITION(S):
RPM 24 or greater.

FAILURE CONDITION(S):
Fuel pump feedback 2 volts or less for 1.3 seconds.

ACTION TAKEN:
1. PCM turns "ON" the "SERVICE VEHICLE SOON" message.
2. IPC turns "ON" the "CHECK INFO CENTER" telltale.

NOTES ON FAULT TREE:
1. Checking for engine to start. If it does, fuel pump 1 relay operates correctly. Either fault is no longer present or CKT 120 to PCM is open. If it does not start, fuel pump 1 relay or circuits are at fault.
2. Checking if CKT 120 is open or if no fault is present.