97 Dodge Intrepid

1997 DODGE INTREPID
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JAMICEBEARD
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I have a dodge intrepid 3.3 liter engine--very often the car will not start. Usually it has to be jumped to start again. i took it to advance auto and returned home with the code p1781! I have no ideal what that means and the guy at advance auto didn't either, his sugestion was to look it up on google, but still i got nowhere!! Could you please help me understand what the problem could be...is it something to do with the starting circuit ie a low battery, bad starter or some bad wires!!! Please help...
Apr 16, 2011 at 11:42 PM
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CARADIODOC
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P1781 – 4x4 Switch Out Of Range. Didn't know you had a 4 wheel drive, did you? Some aftermarket scanners produce erroneous codes. This could be what happened here.

Based on your symptoms, it sounds like you might have a charging system problem. Start by measuring battery voltage while the engine is running. All you need is an inexpensive digital voltmeter. You must find between 13.75 and 14.75 volts. If it is low the battery will not fully recharge while driving. Some simple additional tests will narrow down the cause. If it is within that range, remeasure it with as many electrical accessories turned on as possible or have your mechanic perform a load test on the alternator. Although rare on Chrysler products, if one of the six output diodes is shorted, you will only be able to get very close to one third of the alternator's rated capacity. That could mean less than 30 amps from a 90 amp unit. 30 amps is just barely enough to run the head lights / running lights, fuel pump, injectors and all of the computers leaving nothing left over to run the heater fan, radiator fan, radio, and recharge the battery. That means the battery will discharge as you drive.
Apr 16, 2011 at 11:59 PM
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RASMATAZ
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P1781 Engine Torque Signal Circuit"

very often the car will not start. Is it cranking over and will not start or just won't crank at all/nothing?

Apr 17, 2011 at 12:02 AM
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JAMICEBEARD
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at first when the problem occured it would crank and not turn over...as time progress it would not crank at all, just a clicking noise!!
Apr 17, 2011 at 12:12 AM
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CARADIODOC
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Crank and turn over are the same thing. Think of "turning over" the hand "crank" to start a model T. A clicking noise suggests the starter wasn't spinning the engine. Was it a single kind of loud clunk each time you turned the ignition switch to "crank", or was it a constant, repeated rapid clicking, almost like a buzzing noise?
Apr 17, 2011 at 12:36 AM
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JAMICEBEARD
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yeah it was rapidly clicking, and yes it sounded like buzzing
Apr 17, 2011 at 12:44 AM
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CARADIODOC
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That means not enough current is getting to the starter. Either the battery cables are loose or corroded or the battery is run down from not being recharged.

Measure the battery voltage before starting the engine and when it is running, then holler back with those numbers.
Apr 17, 2011 at 12:49 AM
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