All 1990 E/K/V cars require the use of a special tool to remove and install the SIR forward sensor and the SIR forward sensor mounting bracket. The fasteners used for these components require a size T27 tamper resistant torx bit.
Proper removal and installation procedures are outlined in Section 9JB of the respective vehicles' New Product Service Information Manual. The tool is currently available through Kent-Moore.
Tool
Number Tool Description ------ ---------------- J-38597 T27 Tamper Resistant Torx Bit
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.