OIL PRESSURE GAGE ERRATIC (REPLACE OIL PRESS. SENSOR)

SUBJECT: OIL PRESSURE GAUGE ERRATIC OR DISPLAYS HIGH OIL PRESSURE (REPLACE OIL PRESSURE SENSOR)

VEHICLES AFFECTED: 1986-92 "E" AND "V" MODELS

This bulletin is being revised to add the term "measured oil pressure" beginning with the second paragraph. In addition "BD71 Value" has replaced the term "Parameter Value" through out the bulletin. A new sentence has been added to the second bullet. Both sub-paragraphs under the second bullet have been revised to clarify the text. An Oldsmobile NOTE has been added at the end of the text.

Some 1987-1992 Allantes before VIN breakpoint 135610 and 1986-1991 Toronados, Rivieras, and Reattas may experience a condition where the oil pressure gauge may be erratic (needle fluctuates) or display very high oil pressures. This is due to an internal intermittent contact within the oil pressure sensor.

To diagnose oil pressure gage complaints check the oil pressure with a mechanical gauge using the oil pressure sensor hole in the engine block. The reading you obtain is the measured oil pressure.

o If the measured oil pressure is incorrect according to the engine specifications in Section 6, refer to that section for diagnosis and repair procedures pertaining to high or erratic oil pressure.

o If the measured oil pressure is correct according to the engine specifications in Section 6 of the Service Manual, enter service diagnostics and monitor BCM data parameter BD71. BD71 is oil pressure in psi. BD71 will display a high value with an open or intermittent open sensor and a low value if the BCM oil pressure sensor input is shorted to ground.

- If the BD71 value is steady and agrees with the measured oil pressure, and the intermittent or high instrument panel cluster gage reading is still present, refer to Section 8A-82 of the Service Manual for diagnosis of display conditions.

- If the BD71 value is erratic or at at maximum value, replace the oil pressure sensor with the appropriate part number listed below.

Model Year Carline P/N ---------- ------- ---- 1987-1990 Allante 3532954 1991-1992 Allante 25605389 1986-1990 Toronado, Riviera, Reatta 3532954 1991 Toronado, Riviera, Reatta 25605389

(Oldsmobile Only--NOTE: On Toronado with analog (needle) cluster, an open sensor (fixed high BD71 parameter reading) will result in a high gage reading for a few seconds followed by the needle dropping off to approximately zero to 20 psi. On all other clusters and under all other conditions, the cluster display should agree with the BD71 parameter reading.)

Parts are currently available from CANSPO.

WARRANTY INFORMATION:

Operation VEHICLE SERIES Operation Description Number T R Z E K V --------------------- --------- ----------------------------- Engine Oil Pressure N2220 .4 .3 .3 .2 Switch - Replace

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.