2016 Colorado Move: Mechanical Mishaps

No trip would be complete with out some mechanical issues. Especially on a holiday weekend traveling the loneliest road. Fortunately, the check engine light and the flat tire were not as serious as the failed turbo resonator or transmission breaking.

Check engine light: 

The check engine light came on coming into Carson City, Nevada after dropping down the Sierras. Dave used an OBDII reader to obtain the error codes associated with the check engine light.

Error codes: Cam position sensor, O2 sensor error

Fortunately, where we pulled over in Carson City was not far from the Dodge dealer. The shop manager reviewed the codes and said that the cam position sensor can ‘hiccup’ especially when traveling from high to low altitudes. This results in a cascade effect that causes the O2 sensor to error as well. He was happy to report that as long as the check engine light wasn’t flashing, we could continue to drive Abby. If we wanted peace of mind, we could have it checked out, but the soonest he could get to it would be Tuesday. As much fun as a two night minimum in Carson City sounded, we decided to push onward. We bought a Good Sam towing membership.

Total time lost: 1 hour

Repair difficulty: Easy, it was simply getting advice from a shop guy. Google indicated that replacing the sensors was not difficult and could be done in a parking lot or campsite. No auto part stores had the parts in stock. Abby is due for a thorough tune-up, including a transmission flush, at the end of this trip. We are going to pay the money and let a Dodge dealer give Abby some TLC.

Flat tire:

Flat_01Our flat tire occurred approximately 40 miles west of Austin, NV. We were losing approximately 2 lbs of pressure every mile. How did we know? Dave purchased and installed EEZTire Monitoring system that reports the pressure in each tire via RFID. Fortunately, the Edwards Creek historic marker was close by and we were able to pull over in a safe place to change the tire. As Dave changed the tire, Jess wrangled the dogs and Alex, with marginal success. The dogs had to be returned to Abby. Alex ran around with tools key for changing the tire and found every bit of dirt on the Abby and transferred it to himself. Inspection showed that the valve stem had failed. To add to the fun, the spare tire and the other dualie tire needed to have their pressures increased. Our 12V electric pump burned out; fortunately, we had a bike pump with the appropriate fitting in the trailer.

Flat_02After completing the tire change, we stopped in Austin, NV to fill Abby up. Dave inquired about tire repair and was directed to Wayne, the tire guy. He provides 24/7 service for this isolated area and was able to fix the tire.

Total time lost: 2 hours

Repair difficulty: Easy. If you know how to change a tire on a car, you can change a tire on an RV. Parts are just bigger and heavier, technology and theory are the same. This is a key skill otherwise you will be waiting for several hours in the sun for assistance. And there may be no cell service.

Turbo Resonator Failure: June 2015

Dave working on the turbo resonator.
Dave working on the turbo resonator.


  • Acceleration was not smooth, check engine light came on. Symptoms disappeared on restart of engine.
  • During hill climbs, acceleration decreased dramatically, symptoms disappeared for time after engine restart. Each successive restart resulted in a shorter and shorter time before symptoms represented. Check engine light came on after multiple restarts.

Fault Codes:

  • OBD II P0121: Throttle/Pedal Position Sensor/Switch ‘A’ Circuit Range/Performance Problem
  • OBDII P0299: Engine Turbo-Supercharger Boost
The split turbo resonator. That seam should not have that gap.
The split turbo resonator. That seam should not have that gap.

Problem: The turbo resonator is made of plastic and the seam failed. This is a known failure point according to multiple forums. Mercedes has been through three revisions of this part in plastic and it keeps failing.

Solution: Previous owner had the turbo resonator replaced once by Mercedes dealer and they put in another plastic version. Previous owner decided to purchase an all aluminium replacement part and it transferred to us when we purchased Abby. Repair was simple enough, complicated by rain and being parked in an emergency pull-off area along I-76W. Requires low clearance 1/4″ socket (which we did not have). We limped into Somerset, PA with an escort by a Herring Motor Company tow truck (fortuitously helping an automobile with issues in our emergency pull off), to purchase a $9 socket wrench to properly execute the repair. Dave performed all mechanical repairs. Jess served as chief child and dog wrangler and did not bake cookies while waiting for the repairs to be completed.

Repair Tips/Comments:

  • Still have the plastic turbo resonator in? Just order the all metal version and replace it before it fails on the road. Repairs are always easier on a nice day, parked in your driveway/workshop, without traffic flying by at 70+ mph. An inexpensive repair (if you do it yourself, several hundred at a dealership) that will save you time and headache on the road.
  • This is a repair you can do yourself if you are comfortable doing basic maintenance work on your vehicle. It is two hose clamps. That is it. The working space is tight, which adds to the challenge.
  • Have your outdoor rug easily accessible. It doubles well as a work pad
  • The metal part does whistle. So don’t panic. It may be noisier, but it won’t leave you stranded on the side of the road.