Test M - Fuel Pump Circuit (Inertia Switch)
- Install fuel pressure gauge to Schrader valve. Check if fuel pump runs. Cycle ignition from off to "Run" (DO NOT crank engine) several times. Pump should operate in "Run" mode. If so, check fuel system for problems. If not, go to next step.
- Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and reconnect ECA. Turn ignition on. With DVOM on 20 volt scale, measure voltage between box pin 37 and pin 40 and between box pin 57 and pin 60. If either is less than 10.5 volts, go to TEST B - VEHICLE BATTERY . If both are 10.5 volts or more, go to next step.
- Turn ignition off and wait 10 seconds. Leave breakout box and ECA connected. Locate and disconnect fuel pump inertia switch. With DVOM on 200 ohm scale, measure resistance of switch. If less than 5 ohms, go to next step. If 5 ohms or more, replace inertia switch and repeat Quick Test.
- Turn ignition on (engine off). Leave breakout box and ECA connected. With DVOM on 20 volt scale, measure voltage from chassis ground to power to pump(s) circuit at fuel pump relay while cranking engine. If 8 volts or more during cranking, go to next step. If less than 8 volts during cranking, go to step 6).
- Turn ignition on (engine off). Leave breakout box and ECA connected. With DVOM on 20 volt scale, measure voltage from chassis ground to power to pump(s) circuit at fuel pump(s) while cranking. If 8 volts or more during cranking, service electric fuel pump(s). If less than 8 volts during cranking, repair open in power to pump(s) circuit and repeat Quick Test.
- Turn ignition on (engine off). Leave breakout box and ECA connected. Locate fuel pump relay. With DVOM on 20 volt scale, measure voltage from chassis ground to vehicle power circuit at relay. If 10.5 volts or more, go to next step. If less than 10.5 volts, repair open in vehicle power circuit (between fuel pump relay and ECA) and repeat Quick Test.
- Turn ignition on (engine off). Leave breakout box and ECA connected. Locate fuel pump relay. With DVOM on 20 volt scale, measure voltage from chassis ground to vehicle battery circuit at fuel pump relay. If 10.5 volts or more, go to next step. If less than 10.5 volts, repair open circuit (between relay and battery positive terminal) and repeat Quick Test.
- Turn ignition off and wait 10 seconds. Leave breakout box and ECA connected. Fuel pump relay disconnected. With DVOM on 200 ohm scale, measure resistance of fuel pump relay from fuel pump circuit to box pin 22. If less than 5 ohms, go to next step. If 5 ohms or more, repair open in fuel pump circuit and repeat Quick Test.
- Turn ignition off and wait 10 seconds. Leave breakout box installed and disconnect ECA. Locate and disconnect fuel pump relay. With DVOM on 200,000 ohm scale, measure resistance from box pin 22 to pins 37 and 57. If 10,000 ohms or more, go to next step. If less than 10,000 ohms, repair short to power in fuel pump circuit and reconnect ECA. Attempt to start vehicle. If vehicle does not start, replace ECA and repeat Quick Test.
- Leave breakout box installed and ECA disconnected. Insert jumper wire between box pin 22 and pin 40 (or 60). Turn ignition on (engine off). With DVOM on 20 volt scale, measure voltage from chassis ground to power to pump(s) circuit at fuel pump relay. If 10.5 volts or more, replace ECA and repeat Quick Test. If less than 10.5 volts, replace fuel pump relay, reconnect ECA and repeat Quick Test.