Notes On Intermittents

If PCM Code P020 is stored as history code, unplug oil pressure switch. Start engine and allow to idle. Check relay for proper installation into socket. Manipulate affected wiring. If fault is induced, engine will stall and Code P020 will set. If Code P020 sets without engine stalling, check for intermittent open in circuit No. 120 between PCM terminal 3E13 and splice to fuel pump relay "A" terminal No. 3.

Fig 1: PCM Code P020 Schematic - Open Fuel Pump Circuit

Courtesy of GENERAL MOTORS CORP.

Fig 2: PCM Code P020 Flow Chart (1 Of 3) - Open Fuel Pump Ckt.

Courtesy of GENERAL MOTORS CORP.