Author Topic: Boost Pressure Sensor Short Circuit  (Read 2505 times)

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Offline luckydog1949

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Boost Pressure Sensor Short Circuit
« on: December 06, 2017, 09:28:09 AM »
2005 Itasca Horizon on Freightliner Chassis with CAT C7 350HP (KAL68XXX) and Allison transmission. 

Coach began stumbling, lost power.  Check engine light came on and went off.  Boost gauge showed no boost.  Kept trying to drive for about five minutes, boost gauge pegged at max and dropped to zero, and began getting some boost, again.  Engine smoothed out, but not as strong.  Drove 60 miles home.

Found code 102-04 Boost Pressure Sensor Short Circuit (I believe that the next number "42" shows the number of readings of that code.)

I changed the primary fuel filter and will open under the bed to change out the secondary fuel filter, soon (I don't really think that will help with this; but, it's almost time to change them, anyway.)  Is there anything in particular that I should look/check for on the sensor?  Or, should I go buy a replacement sensor before opening the engine cover?

Thanks for any advice.

Tom

Offline ziggyh

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Re: Boost Pressure Sensor Short Circuit
« Reply #1 on: December 06, 2017, 04:41:59 PM »
Tom, the code sets whenever the signal wire drops below .2 volts for a second or two. It could be because of an open or short to ground in the signal wire or poor connection at the sensor or bad sensor. 

I would carefully look at the connection at the sensor and then for any point in the harness that could be grounding out, ohm out the wire from the sensor back to the ECU while moving the harness around checking if it shorts to ground or goes open.

I think the signal wire is on pin 40 at the ECM on the connector toward the front of the motorhome and pin c at the sensor.
ZiggyH

2007 Revolution LE
C9

Offline luckydog1949

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Re: Boost Pressure Sensor Short Circuit
« Reply #2 on: Yesterday at 12:04:51 PM »
ziggyh, you were on-the-nose with the solution.  I'm moving a lot slower than I used to; but, it did turn out to be a wire going to the boost pressure sensor rubbed and shorting to the valve cover.  It's all good, now.

Offline ziggyh

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Re: Boost Pressure Sensor Short Circuit
« Reply #3 on: Today at 06:36:00 AM »
Awesome, glad to help.
ZiggyH

2007 Revolution LE
C9