2023 Blue Bird Vision School Bus TSBs

Condition:Chassis web fractures in or around the vicinity of the LF shock mount Root Cause Identification and Justification: FEA modeling shows elevated regions of stress in proximity of the upper fastener hole for the LH shock mount resulting from several external influences. The highest stress stemming from shock extension forces in curb hop scenarios. Bearing in mind the absence of this failure mode on standard floor chassis designs with substantially higher usage, the projected stress in this region of 4582 PSI is used as an objective bench mark of the acceptable upper limit. Two corrective solutions are being executed as pragmatic countermeasures to correct this failure mode, based on the severity and frequency of the crack, if present. Repair plate 1 being the latest evolution. FEA analysis & ref chart below Installation of this repair plate decreases the stress in this region to less than the standard floor chassis baseline allowing us to predict this solution to last the expected life of the chassis.

gasket used to seal off the transmission cooler. This deformation is caused from transmission oil wicking through the thread adapter threads and exposing the lower portion of the gasket to transmission oil. Re-configure hydraulic interface between the transmission cooler lines and the transmission oil cooler. SU2302 Revised to include Labor Time of 1 Hour and a Component Code. Incorrect wording on the Header Page beginning on Page 2.

gasket used to seal off the transmission cooler. This deformation is caused from transmission oil wicking through the thread adapter threads and exposing the lower portion of the gasket to transmission oil. Re-configure hydraulic interface between the transmission cooler lines and the transmission oil cooler. SU2302 Revised to include Labor Time of 1 Hour and a Component Code.

seal off the transmission cooler. This deformation is caused from transmission oil wicking through the thread adapter threads and exposing the lower portion of the gasket to transmission oil. Re-configure hydraulic interface between the transmission cooler lines and the transmission oil cooler.

restricting coolant flow through the high voltage propulsion motor.

PATS (Passive Anti-Theft System) or SPM (Security PATS Module) is a new piece of required hardware that has not been used historically on Ford powered Blue Bird Vision Buses. The intent of this memo is to provide a basic overview of its function, purpose, and basic diagnostics. The 7.3L PCM hardware requires a PATS handshake to enable engine crank. The PATS module, sometimes called an SPM, is paralleled to Ford CAN only and not to J1939. Its mounted above the MPX module (non-NEA) within the PDU and on NEA models it is located on the ledge above the chassis PCB. The PATS module is purpose built for non-Ford VIN applications using the 7.3L engine. It is paired to the PCM via an IDS bi-directional function, to which one needs Ford PTS log in credentials for IDS access to the immobilizer database.

sensor replacement parts are not available. This provides a temporary ECM calibration that inhibits engine warning messages for communication errors with the DEF sensor allowing continued operation without engine derate. Regulators are allowing for this temporary calibration to be loaded in the engine ECM by a Cummins authorized repair location if the DEF sensor fails. This temporary calibration does not repair the failure therefore a final repair must be performed and the original calibration be re-installed. Field Service has been requesting an ECM image be uploaded within the support ticket as part of the diagnostics and is carried over into Service Update 2201 (SU2201). In order to receive an authorization code and utilize Cummins TRP2484, you must follow the process, as outlined in SU2201. The specific component affected is Assembly Code: 35-300 Emissions Components.

followed for all Cummins EV powered units. The sequence is required due to multiple electronic modules required to wake up and start communicating over the CAN (Controller Area Network) on EV Power Train Product.

battery loss attributed to CAN Devices not going to sleep. This symptom is occasionally accompanied by the cluster flashing on/off on an approximately 3-minute frequency. Blue Bird and Ametek have developed a software to alleviate this concern.

limitations of the mechanical switch. As a result, a preventative maintenance adjustment procedure is necessary and, at times, settings can be difficult to achieve.

Primary failure seen is deterioration of the EPDM gasket sealing the transmission oil cooler (TOC) to lower radiator tank, which allows a path for coolant to leak externally. Secondary failure seen is cross contamination between coolant and transmission oil. To eliminate the possibility of experiencing this condition, Blue Bird is providing 1 year of coverage to update the transmission oil cooler interface along with a visual inspection of any cross contamination at time of completing the interface update. Please follow the flowchart within the instructions to determine if any additional repair activity is necessary and, if so, complete further repair procedures as stated.

Electric buses now available at Quickserve Online. Dealer must have access to Quickserve to obtain these service maintenance and repair procedures.