Turbo Boost Sensor

[PrevostGator]

I have a 2002 Liberty XL2 45 1 slide. Last week I was on my way to Chicago to have wood floor put in. Friday night going through Atlanta at 6:45 pm (poor planning) my amber engine warning light came on which said check engine at next stop. Very soon after the red shut down engine light came on. I made my way over to the right lane and started up the ramp and the engine cut off. Got out and checked my fluid levels and all was good. Called Troy at Liberty and he had me turn on the key and read the codes which said I had a turbo boost problem.
I cranked the engine up and no lights came on so drove up I-75 around ten miles and spent the night in a Home Depot Parking Lot. The next morning I drove the coach 80 miles north to a Detroit Diesel garage in Ringgold, Ga., exit 350. They called a technician in to have a look. The computer said that my Turbo Boost Sensor was bad so they replaced, and I was on my way. These people were absolutely superb. They normally charge time and a half on Saturday but only charged me straight time of two hours, $200 plus the part $68.
My question is this. Occasionally, the check engine light still comes on, then goes out. The coach is running fine and I continue to watch my fluid levels. Has anyone had a similar problem. I think I must have a loose wire.

[Gary & Peggy Stevens]

PrevostGator; two years ago after I got my 01 XLII it gave me the flashing amber check engine light and I noticed my Turbo Boost Gauge read 0, but the Red Engine light never came on nor did my engine ever completely stop. This was an intermittent thing and over a couple of months.

I took it to S & S and they diagnosed that a code 86 was a High voltage Barometric Code error. They replaced the current sensor with what they said was the correct one? A Dual barometric and Turbo Boost Sensor Unit. Haven't had that problem since then.

Glad you got on the road again.

Gary S.

[merle&louise]

PrevostGator,

My check engine light has been coming on/off for 5 years! I check the fluid levels and as long as they are o.k. I just keep on truckin'. My red stop engine light has never come on nor has the engine ever stopped.

Many people on this forum experience the same thing with the check engine light; the general consensus is that humidity can cause these type of problems. I do think however, that since your engine stopped you had a real sensor failure, and you were right in bringing it into a DD service center.

When the check engine light comes on: check water temp, oil pressure, and all of your gauges. Check your oil, antifreeze, and transmission oil levels before you begin the day of driving and you will probably be fine.

I wouldn't worry about it.

[chtree]

we had a similar sitiuation last summer, took about six weeks and finally found a wire that had a bad spot that would only separate after engine got warm. It was really frustrating. Don't give up you will find the problem!

Good Luck!

Chris

[Jon Wehrenberg]

One of the basic things I learned with the bus a long time ago is to never allow any known defect to go undiagnosed and repaired.

I am dealing with one that has related to my inverters and appears to have self corrected. Despite that I have begun the laborious process of following every cable and wire and checking each and every terminal and connection.

The reason to get to the root cause of problems is when a second one pops up the issue is not doubled, but seems to have increased in complexity exponentially. I don't doubt the turbo boost sensor was an issue, but now another issue seems to have cropped up. Generally codes are retained in memory so I would suggest you consider getting someone to read the codes to see what the intermittent light is trying to tell you. These types of check engine or stop engine lights and codes can sometimes be as simple as a bad wire, wire connection, ground, corrosion, etc. This is where a person can spend an evening or day examining every sensor connection, wire bundle, or DDEC plug looking for corrosion or bad contacts.

Grounds are a special concern and because of the low voltages involved they have to be perfect. Our buses are loaded with potential causes so doing the investigative work is laborious, frustrating, and unsatisfying.

It's akin to finding leaks in the aux air system, only harder.