Engine - PROM Update Improves Hesitation and Instability

18-52
Amended
11/01

DATE: 4/97

MODEL:
XJS (4.0L) 1996 MY

VIN:
222632-226644

Momentary Engine Hesitation instability - Service Action S676

Remove and destroy Bulletin 18-52, dated 4/97. Replace with this Bulletin.

Updated information is shown with asterisks.

ISSUE:

Some 1996 MY XJS vehicles within the above VIN ranges may experience a momentary engine hesitation/instability while cruising at steady highway speeds.

This condition may be accompanied by a very brief illumination of the "Check Engine" Malfunction Indicator Lamp (MIL).

This condition can be rectified by replacing both of the Programmable Read Only Memories (PROMs) with new PROMs from the appropriate modification kit. In addition, this Service Action supersedes S659 (Bulletin 18-49) and S672 (Bulletin 18-51)

ACTION:

* Refer to Technical Bulletin 17-12, amended 11/01. The software revisions for Service Action S676 to solve the above complaint were incorporated in the PROMs designed for Recall R493.*