SUPPORT AS 1155305 - Caterpillar

The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
This Program can only be administered after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS05432" as the Part Number and "7755" as the Group Number. Use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
Termination Date
April 30, 1999Problem
The engine may lug when under load on certain 320B, 322B and 325B Excavators. If the back up mode is switched on and off or if the engine is cut off for a couple of minutes, the fault disappears. That problem is due to stack overflow in the controller.
Affected Product
Model & Identification Number
320B (1XS1-654 6LW1-323 )
320B L (7JR1-982 9WS1-178 )
320B N (2AS1-588)
320B S (5MS1-331)
322B L (2ES1-501)
322B LN (1ZS1-260)
325B L (6DN1-706 4DS1-160 5BS1-219 )
325B LN (8FN1-557)
Parts Needed
1 - 1519343 Control Group (for all 325B)1 - 1519339 Control Group (for all 320B)1 - 1519365 Control Group (for all 322B)Action Required
For 320B, replace the 1327808 or 1393976 with a new 1519339 Control Group. For 322B, replace the 1327810 or 1393980 with a new 1519365 Control Group. For 320B, replace the 1327812 or 1393982 with a new 1519343 Control Group. See Illustration 1.
Service Claim Allowances
This is a 0.5-hour job.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Illustration 1.