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Bronco died need answer

2661 Views 1 Reply 2 Participants Last post by  SigEpBlue
did a code check with a wire to ground. check engine light flashed out these codes 114,116,539,542,&636. I have been racking my brain and looking up things so i don`t have to bother you guys with dumb questions. But this code 542 fuel pump curcuit open pcm motor to ground. Is it possible the power train control module went out? truck quit running while i was driving

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I believe you didn't do the test right. You have to (or at least you're supposed to) have the vehicle at full operating temperature before performing a KOEO self-test. That's probably the reason you see codes 114, 116, and 636. You also probably had your a/c or defroster on, thus code 539.

542 is the only one you need to worry about, and you've got the wrong definition for it (or at least you need some term correction). 542 simply means there is a fuel pump circuit failure, i.e. there's no voltage seen by the PCM going to the fuel pump. This could be as simple as a bad relay or fuse.

Directly from the service literature:

DTC 542 indicates that one of the following has occurred:

No Start:

-- Inertia Fuel Shutoff (IFS) switch not reset or electrically open.

-- Open circuit between the fuel pump and FPM circuit connection to the power-to-pump circuit.

-- Poor fuel pump ground.

-- Fuel pump electrically open.

Engine Starts:

-- Fuel pump secondary circuit short to power.

-- Fuel pump relay contacts always closed.

-- Open in FPM circuit between PCM and connection to the power-to-pump circuit.

-- Left/front HO2S short to power (dual HO2S applications).

-- Damaged Powertrain Control Module (PCM).

l Does the engine start? (For trucks with dual fuel tanks, verify tank selector is in the same position it was when KOEO DTC 542 was received.)

GO to «J11».

GO to «J15».
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