5 Speed Allison Transmission Neutral Safety Switch NSBU for 2001-2004 6.6l Duramax LB7

Also known as a PRNDL switch. If you are getting a "shift range inhibited" message on the message center along with a flashing light under the gear or range you are attempting to shift to, this switch likely needs replaced.

Some of the symptoms of failure include:

No start condition
Gear shift indicator on dash not following properly
Trans stuck in limp mode or fail safe
DTC's set indicating pressure switch codes

The vehicle is equipped with a column type shift selector. In addition to the column shifter, another component associated with the shift selector is the Neutral Start Back Up (NSBU)switch mounted on the selector shaft of the transmission. The NSBU switch transmits selector position information to the TCM. The NSBU switch mounts directly onto the transmission housing, from the outside, and detects the angular position of the shift selector shaft. This position is communicated to the TCM so that certain vehicle control functions can be coordinated with the position of the shift controls. The neutral signal output of the NSBU switch is typically used as confirmation that the transmission is in NEUTRAL or PARK before the engine starter is engaged.

Common trouble codes associated with NSBU failure include:
DTC P0708, Neutral start/backup (PNP or NSBU) switch
DTC P0847, Pressure Switch Manifold (PSM)
DTC P0872, Pressure Switch Manifold (PSM)
DTC P0875, Pressure Switch Manifold (PSM)
DTC P1711, Pressure Switch Manifold (PSM)
DTC P1713, Pressure Switch Manifold (PSM)
DTC U1000, Serial Data Communications
Blank PRNDL Display
Flashing PRNDL Display
Slow or No Engagement of Automatic Transmission

Fits: 2001-2004 6.6l Duramax LB7 with 5 Speed Allison Transmission