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Your powertrain control module (PCM) is down for whatever reason. The PCM is the silver module mounted to the center of the firewall and controls all engine functions. If it's down then you won't have spark, fuel pressure, the fuel gauge and voltmeter won't work and you'll see the no bus message because the PCM isn't communicating with other modules over the bus.

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The problem could be internal in the PCM or external and some electrical testing would have to be done to know for sure where the problem is.

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It could have lost a power or ground feed from a blown fuse, ignition switch, or wiring problem.

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If the 5v reference circuit shorts to ground then the PCM can't wake up. The 5v reference circuit goes to most sensors on the engine and one in the trans. A shorted 5v reference circuit can be an internally shorted sensor or a wiring problem.

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It could be the sensor ground circuit shorted to voltage, which again will prevent the PCM from waking up. The sensor ground circuit goes to most sensors on the engine and trans, again a short on this circuit could be an internally shorted sensor or wiring problem.

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If everything checks out ok then the only remaining cause would be the PCM, which is the most likely cause for the problem.

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