Unit is a 2000 National RV Tradewinds on a Freightliner chassis w/Allison tranny.
My faithful CAT 3126B has triggered the "check engine" light. I'd like to find out what the error is to determine the severity and whether I can safely drive it to a maintenance shop (nearest that sounds qualified is about 75 miles away) or not. Local truck shop couldn't find the port for their electronic diagnostic computer (I think from reading other forum I now know where that is) BUT, my manual says I can use the cruise control switch to make the check engine light blink out the code. So far, all I can make it do is blink on for 5 seconds, off for about 2 seconds, and repeat endlessly.
No code display like the manual says there should be. Does anyone have any experience with this or any suggestions on how best to proceed?
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On some chassis if the coolant level is low it will turn on the check engine light but not set codes. Coolant level switch is located in the radiator expansion tank.
If the chassis paperwork , has steps to read the codes and they aren't working ; best would be to call the free Freightliner Help Line with your serial number, and have them talk you through the process or send you an updated method.
1-800-FTL-HELP
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99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
If the chassis paperwork , has steps to read the codes and they aren't working ; best would be to call the free Freightliner Help Line with your serial number, and have them talk you through the process or send you an updated method.
1-800-FTL-HELP
Great idea, thanks. It didn't occur to me that Freightliner would be the one to answer this question, will give them a try.
Great idea, thanks. It didn't occur to me that Freightliner would be the one to answer this question, will give them a try.
UPDATE: I figured out how to make the codes appear on the dashboard (have to read the instructions fully and carefully) and am getting 34 "Engine RPM Signal Fault", 39 - "Injection Actuation Pressure System Fault" and 15 - "Injection Actuation Pressure Sensor Fault." (Seems possible to me that 39 and 15 are closely related and might be a sensor problem.)
I called Freightliner, and while the technician was very nice, he admitted they didn't have much info on Caterpillar engines, in fact I had to read him the fault titles from my Cat book. He did say (after talking with another tech) that as long as the STOP ENGINE light hadn't illuminated, I should be able to drive to my nearest Freightliner Oasis dealer 75 miles away.
So, just wondering if any of you have knowledge of these faults and the advisability of driving with them for 75 or so miles?
The engine RPM sensor is a bear to access if your coach has an air compressor for air brakes and suspension . The engine uses two sensors, RPM and cam , to avoid shut down in the event of one failing . The IAP sensor is an easy change and I'd thing that should take care of both codes.
Diagram shows engine speed sensors ; with air compressor not shown; they are behind the air compressor.
Driving the coach should not be an issue , but I'd avoid any WOT ( Wide Open Throttle ) because the high rpm might result in pressure from the pump high enough to damage the injectors.
I don't know this for a fact , JMHO.
If the shop you're headed to has a Cat specialist , he'd be the one to ask.
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99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
It did take me quite a while under the dash to find the diagnostic connector , it was just tucked in with the rest of the dash harness ; buried.
Another thing I found , while greasing the drive shaft U joints was a 7' loop of wiring on top of the transmission , with a second diagnostic connector. I ran the wiring up the side of the trans dipstick tube and secured the connector beside the dipstick , so there is a connector at both ends of the coach.
I don't know if you'll have one at the rear , I've been caught up with wiring differences between National and Newmar, on F/L chassis before, but it would be worth looking around at the rear, of you coach.
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99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
It did take me quite a while under the dash to find the diagnostic connector , it was just tucked in with the rest of the dash harness ; buried.
Another thing I found , while greasing the drive shaft U joints was a 7' loop of wiring on top of the transmission , with a second diagnostic connector. I ran the wiring up the side of the trans dipstick tube and secured the connector beside the dipstick , so there is a connector at both ends of the coach.
I don't know if you'll have one at the rear , I've been caught up with wiring differences between National and Newmar, on F/L chassis before, but it would be worth looking around at the rear, of you coach.
Skip: On way back from required safety inspection and getting ready to take RV to Freightliner, I noticed a recurring "ding" "ding" coming from somewhere but no other indications other than the flashing "check engine" light. I read through all the CAT and owners manuals today and can't really find any reference to this audible "dinging." There is no "Stop Engine" light, so not sure what this alarm is supposed to tell me. Also, now I note that the RV has very little power, in fact, it got stuck in our wet mud and won't even try to pull out. Have I entered the "derating" stage on the engine? Is there any type of temporary reset to at least get her out of the soft ground?
The light bar on my dash has , warning lights for " Check Engine" , " Stop Engine " and " Engine Protect ".
I can't think that the Cat ECM would go into , de-rate power mode , without the other lights coming on .
I'll re-read the pdf , that I attached, and go through the list of faults that will trigger a de-rate ; those marked with the ( X ) rather than those with a ( *), and cross reference them with the codes you reported .
In the mean time you could look at the connections from the turbo to the CAC ( Charge Air Cooler ) and to the intake manifold . A sudden loss of power with no , Engine Protect light on, may be an issue with an air pressure leak between the turbo and the intake. Could be a clamp or a leak from the flex joints or the CAC.
I'll go through what I have on the chassis , but I'm sure my chassis uses buzzers , to supliment any dash warning lights , not a " dinger " , and my buzzers are too loud to ignore.
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99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Ok after reading the pdf , I have to ask questions .
In you post you listed a, code 39 as IAP system fault , the chart lists that code as 19 . Was that a typo on your part ?
Because I don't see a code 39 on the chart.
According to the chart the ; code 15 ; IAP Sensor fault can result in low power.
and the code 34 Engine Speed sensor , will shut the engine down .
If you don't find any issues , with the connections between the turbo and the intake manifold , then the next step would be to replace the IAP sensor , and that's a fairly easy DIY job . The sensor location is in the diagram I posted and I'll see if it shows up in any of the pictures I have of my engine.
EDIT: I got back in time to add a photo to this post .
This is a picture showing the IAP Sensor ( yellow circle ) on a C-7 , but the location of the sensor is the same as a 3126B . Passenger side of the engine , beside the valve cover.
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99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Ok , found another Cat engine code document with the 39 code, IAP system fault, and this document doesn't have a listing for a code 19, like mine does.
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99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Thanks so much for your research, pix, and suggestions. Interestingly enough, I let the RV sit for a day (approx. 24 hours, remember it was stuck in soft ground). I then was able to use the leveling jacks to raise the wheels and put timbers under them. Started her up, and she had all her old power and "walked" right out of the mud into her parking place. Of course, I'm sure it's not fixed as all the codes are still there. The problem seems to arise after about 10-15 minutes of "normal"operation. The dinging is a bafflement. I, too have the obnoxious buzzer that you can't ignore, but it's not coming on. Will let you know what I find out as I progress, but at least I'm not stuck anymore. Thanks again, this has been a bit unnerving.
Linear Mode
