Fuel Pump Relay, no signal from computer
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Fuel Pump Relay, no signal from computer
Hey all,
Troubleshooting a 96 Ram, 5.2L, 4x4.
Cranks, but will not start. Fuel pump not receiving power, traced problem back to the fuel pump relay. It is not receiving signal from the computer to supply power to the fuel pump
Haven't had a chance to verify continuity of wiring from the relay to the computer, but assuming that's good, can I be confident it's the computer, or are the other conditions/components I have to check?
(the only anctive code is P0505 "idle air control")
Thanks for any help.
Troubleshooting a 96 Ram, 5.2L, 4x4.
Cranks, but will not start. Fuel pump not receiving power, traced problem back to the fuel pump relay. It is not receiving signal from the computer to supply power to the fuel pump
Haven't had a chance to verify continuity of wiring from the relay to the computer, but assuming that's good, can I be confident it's the computer, or are the other conditions/components I have to check?
(the only anctive code is P0505 "idle air control")
Thanks for any help.
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Joined: Apr 2010
Posts: 87,465
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From: Clayton MI
P0505 code CAN be a toasted computer......
PCM should trip the fuel pump relay for three seconds when the key is first turned on. It grounds the control circuit to trigger the relay. That can be easily tested with a test lite. (put the clip on the + battery terminal, plug the probe into the cavity for the ground side of the circuit where the relay mounts, turn the key on. Lite should come on for three seconds....)
If you are getting power to the coil, and injectors while cranking, but, not getting the relay control circuit triggered, that is more than likely a bad PCM.
PCM should trip the fuel pump relay for three seconds when the key is first turned on. It grounds the control circuit to trigger the relay. That can be easily tested with a test lite. (put the clip on the + battery terminal, plug the probe into the cavity for the ground side of the circuit where the relay mounts, turn the key on. Lite should come on for three seconds....)
If you are getting power to the coil, and injectors while cranking, but, not getting the relay control circuit triggered, that is more than likely a bad PCM.