Freightliner Cascadia, odometer racks up mileage when the vehicle is stationary

Applicable Vehicles

EPA 2007 Cascadia

Symptoms

Odometer racks up mileage when the vehicle is stationary, and/or other gauge issues such as a fluctuating boost gauge or voltmeter.

Discussion

To understand this issue, some background is necessary.  On EPA 2007 vehicles, the engine broadcasts data on both the J1587 and J1939 datalinks.  ICUs on EPA 2007 vehicles receive data from the engine via J1587.  On EPA 2010 vehicles, the engine broadcasts data on the J1939 datalink only.  ICUs on EPA 2010 vehicles receive data from the engine via J1939.  Some customers purchasing EPA 2010 vehicles still had a need for J1587 engine data for satellite communication systems such as Qualcomm.  To meet this need, Freightliner incorporated new functionality into the EPA 2010 Central Gateway (CGW) to rebroadcast J1939 engine data onto the J1587 datalink.

This causes no issues with EPA 2010 vehicles.  However, if an EPA 2007 vehicle is upgraded with one of these EPA 2010 CGWs, problems such as the symptoms described can occur.  The reason for this is the ICU in an EPA 2007 vehicle that has been upgraded with an EPA 2010 CGW will receive J1587 engine data from two sources:  (1) directly from the engine, and (2) from the CGW based on rerouted J1939 data from the engine.  Since the ICU receives the data from two sources, conflicts can occur which may result in the symptoms described.  The solution is to disconnect J1587 from the CGW on EPA 2007 vehicles that have been upgraded with an EPA 2010 CGW.

Solution

If a CGW part number A06-74995-XXX (EPA 2010 CGW) has been installed in an EPA 2007 Cascadia, you must disconnect the J1587 datalink from the CGW.

NOTE:  See the note in Service Bulletin 54-239 which addresses this.

NOTE:  EPA 2007 Cascadias originally came with CGW part numbers A06-60974-XXX (EPA 2007 CGW).