I Hate an Intermittant Problem

[Just Plain Jeff]

JDUB:

Remember that PASS/ACTION card I sent you that you were supposed to keep in the bus?

This might be a good time you make a coupla calls to DD/Prevost?

[Jerry Winchester]

I am going to jumper the reader today and see if I can get the codes. I thought about low oil pressure, but I didn't know how it got the info (from the pressure sender or from another source).

The engine holds 45-50 psi of oil pressure running down the road and about 60 psi when you first start it up and it is cold.

Is there a sensor for any of the transmission functions? The trans fluid level looks ok, so I can't think of a reason it would be an issue, but a faulty sensor at any location could be an issue.

Its a snowy Monday in Jackson and with it being a holiday I doubt any help is available here, but I will see if I can roust anyone at Prevost for some info. I know a guy with DD in OKC, but they won't be in until in the morning.

Lots of "Friends of the Earth" types up here. Lou would be right at home.

[Jon Wehrenberg]

Your transmission has a separate warning light. I also think if you have a transmission problem you may have the "do not shift" light up on the gear selector pad.

I think it is a round gear looking symbol. I suspect your problem is not a problem, but a defective sensor.

Codes, my man, codes.

[Jerry Winchester]

Well it's a good news bad news kind of deal. Finally located the guy with the DDEC code reader. He had to drive over from Idaho Falls to Jackson. Not a nice drive.

Anyway, he shows up with the unit, we open the door where the DDEC plug is and he says, "*(*#$@". He goes back to the box where the $7000 snazzy reader of any codes on any engine and guess what? The plug for the DDECII is not amongst the myriad of plugs with the unit. Book shows the plug, but it isn't in the kit.

Not being one to punt so easy, we go flip the switch and count the flashes to get the codes. However, the snazzy unit doesn't have a book with the codes since the unit is supposed to just tell you what the problem is. However, one of the "example" readouts lists Code 36 - Low Engine Oil Pressure and low and behold, we have code 36 on our list.

I had already surmised this after chatting with Jon. I started the engine this afternoon after a day of sub 40 degree weather and of course the idle oil pressure was in the mid 40 psi and there were no fault lights on, so the deduction was the oil pressure sensor.

And the mechanic said the same thing, so he is going to order one tomorrow and we are going to stop by on our way from Yellowstone to Salt Lake and have him install the new sensor and read the codes with the snazzy reader with the correct plug. What a pain.

Anyway, the codes were 43, 45, 16, 31, 32 and 36. We will know tomorrow what the other codes mean and then we will erase them Friday and start over.

22 inches of snow in Yellowstone last night, so we may not get there tomorrow if they don't get the roads plowed tonight. However the weather is forecast to improve. It even snowed today in Jackson. And it was 96 when we left Houston. Thank god we fixed that AquaHot at the POG rally.

[Jon Wehrenberg]

From my book for DDEC III:

43 Coolant level low
45 OIL PRESSURE LOW....I'll bet that is the sensor problem
16 Coolant level circuit failed high
31 Multiple aux. output issues
32 SEL open circuit or short to battery
36 Oil pressure failed high

The following is speculation: The coolant codes may have been from the previous problem and the 16 code is possibly from tying the terminals together. 36 may be because you were playing with the sensor or it might indicate the sensor is bad.

[truk4u]

Jerry,
Hang in there, we're all learning something. Amazing the temps and snow where your at, we're cooking here in GA. Just came back from 5 days at Charlotte for the race and 90 every day. With all that snow, must be your having a blast with the Hummer.

[Jerry Winchester]

Jon,

The mechanic confirmed the codes you have are correct. I actually think all the codes are the same for all engines as there is some kind of standard for this deal. Except the plugs, so he will have the correct plug when we get there Friday. Go figure.

I think the sensor replacement will be the ticket, but we are going to read and erase the codes, drive the coach with the bad sensor to get it in the clean memory then download the codes again and replace the sensor.

That way we can see if or how the codes are related.

I also have to think there is a simpler, less expensive code reader for this engine. I will check with United Engines and see what they know. We buy enough crap from them at work to warrant a little customer service for the CEO.

Sun is up this morning and it is already 41 deg. so I hope we can stick to the original schedule and motor on to Yellowstone. And yes Tom, this is exactly why we bought the Hummer, so we have had a large time in it as it looks battle weary from all the slush / mud. There is no bling out today. The coach is covered in crud and I can't do a MangoMike and wash it in place (park rules) and I won't be able to do it in Yellowstone, so it looks like the return to bling will be in Salt Lake or Las Vegas.

And Lew, someone is flying a radial engine biplane over town this morning. VP Cheney showed up here yesterday, but I didn't see him at the gunfight on Main Street..........

[Jon Wehrenberg]

Jerry,

As a confirmed tool collector, I am still a ways from getting a reader. You are in the midst of a run of codes, and once you have developed the answers and experience you will find that as long as you know the trick to flashing your codes you will be able to sort out the problem.

A reader is a pure luxury in that it will go beyond the code and give a value, such as how low the oil pressure was or how hot the transmission got.

If you monitor your gauges and are alert to your warning lights and can do what you need to read the codes in your bus you are probably 99% capable of addressing the problem.

If you insist on buying a reader check ebay. I often see them there. At one time a new one from DD was $700 but I'm sure that has changed.

[Jerry Winchester]

Got to Idaho Falls today and hooked up the reader and yes this was the culprit.

Failed Oil Pressure Sensor


We found it with this



You plug it in here....



And in the end, it tells you to replace the old one with this one



Now we are humming down the road headed to Salt Lake City. The sensor was $79. The service call from Idaho Falls to Jackson, WY on Memorial Day was $500. And those aren't LewBucks.

[truk4u]

Excellent Jerry, the 8V guys ought to just change theirs out as PM. Hey Jon, did you notice clean non-grease hands. Must be Rae does the dirty work like Nancy.