sclord2002 Posted December 14, 2019 Report Share Posted December 14, 2019 (edited) While heading home form Charleston,SC, in my 2006 Volvo 780, my front air tank gauge dropped to zero, the warning sounded and the display said low system air pressure. i immediately pulled over and began to ponder the situation. I left the truck running and walked around the truck trying to listen for an air leak....no luck. I looked under the hood and every thing looked ok. I then shut the truck down and listened for leaks...no good, again. I pulled the moisture drain cable on the front and rear tanks and both had pressure and no moisture, The rear tank pressure gauge was normal and cycling normally. I then proceeded to cycle the key off and on to observe the gauge check process. After cycling the key 4 times the front tank air gauge displayed normal pressure and cycled normally as the air governor called for air. I drove off and after about 10 miles, the front tank gauge dropprd to zero just as before, but this time there was not a good shoulder to pull off on, so I nervously continued on, expecting some kind of negative brake action.....nothing occured with the brakes but the alarm is not a good thing to listen to. I pulled into a truck stop and cycled the key several more times and the front air tank gauge started showing some pressure but not as much as the rear tank. I asked a mechanic at the truck stop about it and he said it sounded like a flaky pressure transducer. I continued the remaining 70 miles home with the rear tank gauge normal and the front tank gauge reading about half of that. Time and weather are preventing me from attacking the problem but I can't stop thinking about it. I would be grateful if someone with more air brake knowledge than I have would share their thoughts on this. Thanks in advance. Charlie Edited December 14, 2019 by sclord2002 spelling Quote Don't ever tell a soldier that he doesn't understand the cost of war. Link to comment Share on other sites More sharing options...
Darryl&Rita Posted December 14, 2019 Report Share Posted December 14, 2019 Pressure sensor. Quote I have been wrong before, I'll probably be wrong again. 2000 Kenworth T 2000 w/N-14 and 10 speed Gen1 Autoshift, deck built by Star Fabrication 2006 smart fourtwo cdi cabriolet 2007 32.5' Fleetwood QuantumPlease e-mail us here. Link to comment Share on other sites More sharing options...
sclord2002 Posted December 14, 2019 Author Report Share Posted December 14, 2019 Thanks, Darryl. Quote Don't ever tell a soldier that he doesn't understand the cost of war. Link to comment Share on other sites More sharing options...
Nigel Posted December 14, 2019 Report Share Posted December 14, 2019 (edited) I agree with Darryl. Had a similar situation except mine acted up on a start from cold. Front gauge wouldn’t climb from zero and alarm wouldn’t stop but lots of air in tank. The sensor is inside the cab in front of your left foot where the air lines pass through. There are a couple there and I think I disconnected one at a time, applied brakes and checked gauges to figure out which one it was. Nigel Edited December 14, 2019 by Nigel Quote 2006 Volvo VNL 430, 2006 smart cabrio cdi, 2000 Triple E Topaz 30' Link to comment Share on other sites More sharing options...
sclord2002 Posted December 14, 2019 Author Report Share Posted December 14, 2019 Good info, Nigel, Thanks, Quote Don't ever tell a soldier that he doesn't understand the cost of war. Link to comment Share on other sites More sharing options...
alan0043 Posted December 14, 2019 Report Share Posted December 14, 2019 Hi Charlie, Please keep us update on what you found and how you went and made the repairs. Curious minds need to know. It almost sounds like you might need to remove the left bottom part of the dash to get to where the sensor could be. Best of luck on the repairs, Al Quote 2012 Volvo VNL 630 w/ I-Shift; D13 engine; " Veeger " Redwood, model 3401R ; 5th Wheel Trailer, " Dead Wood " 2006 Smart Car " Killer Frog " Link to comment Share on other sites More sharing options...
Parrformance Posted December 14, 2019 Report Share Posted December 14, 2019 Is the sensor on the inside cab side of the passthrough? Quote 2006 Volvo VNL 780, " Arvey" Volvo D12, 465hp, 1650 ft/lbs tq., ultrashift 2003 Jeep Wrangler Rubicon 2010 Forest River Coachman Freedom Express 280RLS Jackalopee Link to comment Share on other sites More sharing options...
Darryl&Rita Posted December 14, 2019 Report Share Posted December 14, 2019 Not 100% sure on Volvo's, but it should be inside the cab. Follow the line back from the gauge on the tank that's acting up. It should come to a manifold, follow the 2nd 1/4" line to the sensor. Quote I have been wrong before, I'll probably be wrong again. 2000 Kenworth T 2000 w/N-14 and 10 speed Gen1 Autoshift, deck built by Star Fabrication 2006 smart fourtwo cdi cabriolet 2007 32.5' Fleetwood QuantumPlease e-mail us here. Link to comment Share on other sites More sharing options...
Nigel Posted December 15, 2019 Report Share Posted December 15, 2019 1 hour ago, Parrformance said: Is the sensor on the inside cab side of the passthrough? Exactly Quote 2006 Volvo VNL 430, 2006 smart cabrio cdi, 2000 Triple E Topaz 30' Link to comment Share on other sites More sharing options...
RandyA Posted December 16, 2019 Report Share Posted December 16, 2019 Charlie, pressing the "ESC" button on the wiper stalk should temporarily silence the warning buzzer. Probably too late to bring that up since you are back home. I can't imagine driving 70 miles with that thing screaming - it would make one crazy! Quote Randy, Nancy and Oscar "The Great White" - 2004 Volvo VNL670, D12, 10-speed, converted to single axle pulling a Keystone Cambridge 5th wheel, 40', 4 slides and about 19,000# with empty tanks. ARS - WB4BZX, Electrical Engineer, Master Electrician, D.Ed., Professor Emeritus - Happily Retired! Link to comment Share on other sites More sharing options...
adept99 Posted December 21, 2019 Report Share Posted December 21, 2019 Randy; It is, after all, Charlie the Tool Man. My advice for him is to start with a large hammer and work on getting the purge valve(s) to work properly. If that doesn't work, get drunk. See ya'll at the rally Paul Quote Paul & Paula + Daisy the amazing wiggle worm dog... 2001 Volvo 770 Autoshift, Singled, w/ Aluminum Bed - Toy Draggin 2013 395AMP XLR Thunderbolt Toy Hauler 2013 Smart Passion 2012 CanAm Spyder RT 2013 Harley Davidson Street Glide Link to comment Share on other sites More sharing options...
alan0043 Posted December 22, 2019 Report Share Posted December 22, 2019 22 hours ago, adept99 said: Randy; It is, after all, Charlie the Tool Man. My advice for him is to start with a large hammer and work on getting the purge valve(s) to work properly. If that doesn't work, get drunk. See ya'll at the rally Paul LOL. Al Quote 2012 Volvo VNL 630 w/ I-Shift; D13 engine; " Veeger " Redwood, model 3401R ; 5th Wheel Trailer, " Dead Wood " 2006 Smart Car " Killer Frog " Link to comment Share on other sites More sharing options...
alan0043 Posted December 24, 2019 Report Share Posted December 24, 2019 Hi Charlie, I was curious to know, how are you making out with the repair. Did you find the sensor ? Al Quote 2012 Volvo VNL 630 w/ I-Shift; D13 engine; " Veeger " Redwood, model 3401R ; 5th Wheel Trailer, " Dead Wood " 2006 Smart Car " Killer Frog " Link to comment Share on other sites More sharing options...
sclord2002 Posted December 24, 2019 Author Report Share Posted December 24, 2019 Al, I have ordered the sensor. Quote Don't ever tell a soldier that he doesn't understand the cost of war. Link to comment Share on other sites More sharing options...
alan0043 Posted December 25, 2019 Report Share Posted December 25, 2019 18 hours ago, sclord2002 said: Al, I have ordered the sensor. Hi Charlie, good to know that you are on top of it. I think you will have a story this coming spring. Al Quote 2012 Volvo VNL 630 w/ I-Shift; D13 engine; " Veeger " Redwood, model 3401R ; 5th Wheel Trailer, " Dead Wood " 2006 Smart Car " Killer Frog " Link to comment Share on other sites More sharing options...
sclord2002 Posted January 13, 2020 Author Report Share Posted January 13, 2020 Replaced air pressure sensor.....resolved problem. Darryl was right on target. Thanks !! Charlie Quote Don't ever tell a soldier that he doesn't understand the cost of war. Link to comment Share on other sites More sharing options...
Parrformance Posted January 13, 2020 Report Share Posted January 13, 2020 Thank you for the update:) Quote 2006 Volvo VNL 780, " Arvey" Volvo D12, 465hp, 1650 ft/lbs tq., ultrashift 2003 Jeep Wrangler Rubicon 2010 Forest River Coachman Freedom Express 280RLS Jackalopee Link to comment Share on other sites More sharing options...
alan0043 Posted January 13, 2020 Report Share Posted January 13, 2020 2 hours ago, sclord2002 said: Replaced air pressure sensor.....resolved problem. Darryl was right on target. Thanks !! Charlie Hi Charlie, Was the part located inside the truck on the left side of the dash ? Curious minds need to know. Good to hear to the is repaired. Al Quote 2012 Volvo VNL 630 w/ I-Shift; D13 engine; " Veeger " Redwood, model 3401R ; 5th Wheel Trailer, " Dead Wood " 2006 Smart Car " Killer Frog " Link to comment Share on other sites More sharing options...
Parrformance Posted January 13, 2020 Report Share Posted January 13, 2020 (edited) Like this one? Edited January 13, 2020 by Parrformance wrong photo Quote 2006 Volvo VNL 780, " Arvey" Volvo D12, 465hp, 1650 ft/lbs tq., ultrashift 2003 Jeep Wrangler Rubicon 2010 Forest River Coachman Freedom Express 280RLS Jackalopee Link to comment Share on other sites More sharing options...
Darryl&Rita Posted January 14, 2020 Report Share Posted January 14, 2020 14 hours ago, sclord2002 said: Replaced air pressure sensor.....resolved problem. Darryl was right on target. Thanks !! Charlie Sometimes I just get lucky. Quote I have been wrong before, I'll probably be wrong again. 2000 Kenworth T 2000 w/N-14 and 10 speed Gen1 Autoshift, deck built by Star Fabrication 2006 smart fourtwo cdi cabriolet 2007 32.5' Fleetwood QuantumPlease e-mail us here. Link to comment Share on other sites More sharing options...
sclord2002 Posted January 16, 2020 Author Report Share Posted January 16, 2020 Darryl, don't be so modest.....when you are good, you are good !! Thanks. Quote Don't ever tell a soldier that he doesn't understand the cost of war. Link to comment Share on other sites More sharing options...
Scrap Posted January 16, 2020 Report Share Posted January 16, 2020 So what are we looking at in the Volvo pic above? Brake light switch on the top? Park brake switch on the left? Primary and secondary transducers down below? They case ground these things with that ring terminal above? Or is that something else? Quote Link to comment Share on other sites More sharing options...
Parrformance Posted January 16, 2020 Report Share Posted January 16, 2020 The passthrough(Volvo) under the dash above your left foot. Quote 2006 Volvo VNL 780, " Arvey" Volvo D12, 465hp, 1650 ft/lbs tq., ultrashift 2003 Jeep Wrangler Rubicon 2010 Forest River Coachman Freedom Express 280RLS Jackalopee Link to comment Share on other sites More sharing options...
Darryl&Rita Posted January 16, 2020 Report Share Posted January 16, 2020 1 hour ago, Parrformance said: The passthrough(Volvo) under the dash above your left foot. But what does what? Quote I have been wrong before, I'll probably be wrong again. 2000 Kenworth T 2000 w/N-14 and 10 speed Gen1 Autoshift, deck built by Star Fabrication 2006 smart fourtwo cdi cabriolet 2007 32.5' Fleetwood QuantumPlease e-mail us here. Link to comment Share on other sites More sharing options...
rickeieio Posted January 17, 2020 Report Share Posted January 17, 2020 2 hours ago, Darryl&Rita said: But what does what? We keep forgetting, you Kenworth guys don't have the Secret Decoder Ring.😋 That doesn't look like the one in our truck. Plus, the one above is cleaner. Quote KW T-680, POPEMOBILE Newmar X-Aire, VATICAN Lots of old motorcycles, Moto Guzzi Griso and Spyder F3 currently in the front row Young enough to play in the dirt as a retired farmer. contact me at rickeieio1@comcast.net Link to comment Share on other sites More sharing options...
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