SCAN TOOL UPDATE INFORMATION

This Bulletin supersedes DSIB 87-I-40, which should be destroyed.

This Bulletin is an update of the information in DSIB 87-I-6, dated September, 1986.

Scan Tools On 1987 Cimarrons

- Some scan tools used on early 1987 Cimarrons may not be able to read data. To correct this condition, the data line, circuit 461, must be moved from cavity E to cavity M of the car's ALDL connector.

- When a scan tool is used on 1985-1987 Cimarrons with digital clusters, display operation will be temporarily affected. The RPM, Volts and Coolant Temperature displays are calculated from an ECM data stream. Connection of scan tools may cause the ECM to alter this data stream, temporarily changing the display (on 1987 Cimarron, the affected displays will flash at about 2Hz). This condition is normal. Disconnecting the tool will return the display to normal operation.

OTC Monitor 2000

The OTC Monitor 2000 may intermittently flash "NO DATA" when used on a 1987 Cimarron equipped with a digital instrument cluster. This is a normal condition caused by the OTC Monitor 2000 cartridge.

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.