Technical PSI Bulletins Issued In October
TECHNICAL PSI BULLETINS ISSUED IN OCTOBER
New ISAT Program Board and Cable
A new ISAT program board has been developed to support 1992 model applications and provide capacity for future requirements. The new board is redesigned and incorporates an additional memory module which expands ISAT's memory capabilities, permitting multiple languages on one board.
An adapter cable has also been introduced which is required for calibrating the Electronic Throttle System (ETS) with ISAT. The cable ensures continued ISAT communication while the engine is started during the ETS calibration procedure.
See PSI 10/91-0137 for part number and pricing information.
Minimizing Top Fabric Wear - 900 Convertible
When the convertible is driven with the top down, a certain amount of wear may occur in the top fabric. This wear is caused by the eccentric screws (the screws for adjusting the parking position of the top when it is raised) coming into contact with the top fabric when the top is down. On cars from VIN M7018385, the eccentric screws are repositioned so they cannot cause any wear on the top fabric.
On cars with VIN M7018384 and lower, a spacer, P/N 41 54 787, can be fitted at the top mechanism's stop position when the top is lowered. When installed, the fabric is not folded as tightly and does not come into contact with the eccentric screws.
This spacer should be installed and the top adjusted as described in PSI 10/91-0138 whenever there is a complaint of minor fabric wear, when the top is adjusted for any reason or whenever the top fabric is replaced.
Improving Taillight Ground Circuit - 900
On 900 sedan models (2-door, 4-door and Convertibles), the ground circuit for both taillight assemblies is combined in one connection on the left-hand taillight. If there is a poor ground connection, the current load may cause overheating at the electrical connector and subsequent damage to the plastic taillight circuit board. The symptoms of a poor ground circuit can include a dimming of the taillights when the brake lights are illuminated, all taillights blinking in conjunction with a turn signal, or reduced intensity of all taillights.
On cars where overheating at the left-hand taillight has occurred for this reason, follow the procedure in PSI 10/91-0140 to revise the taillight grounds in conjunction with replacing the left-hand taillight circuit board. The revised ground circuit will also be introduced into M92 production.
Correction to 1992 9000 Owner's Manual - 9000
On M92 9000 models, the instrument lighting will only be illuminated when the headlight switch is in the parking light position or the headlight position. PSI 10/91 -0141 was issued to inform you that the 9000 Owner's Manual incorrectly states that the dash lights will always be illuminated when the key is switched on.
Please make sure all dealership personnel are aware of this feature on 1992 9000 models to avoid any confusion and misinformation being passed to customers.
Error Message On Electronic Display Unit (EDU) - 9000
In certain cases, it is possible for the electronic display unit (EDU) in 9000 models to display an error message with an oil temperature symbol or it could display an error message for "sport normal." When diagnosed with ISAT, Fault Code 46222/26222 is retrieved. Neither of these "false" error displays (oil temperature symbol and sport normal) necessarily means that there is something wrong with the unit.
Some EDU's have posssible future functions incorporated into their logic. The EDU is trying to read a signal that is not present, therefore an error message is generated. If for any reason the EDU is not properly programmed from the factory to ignore these future functions, the EDU will try to read a signal that the car is not capable of generating.
See PSI 10/91-0142 for the service procedure should this situation be encountered.
Fuel Pulsation Noise - 9000
Some 1990- 9000 vehicles equipped with the 2.3 liter engine may develop a pulsation noise that can be heard inside the car. Customer complaints often refer to a tapping or knocking sound that is heard when the car is idling at a stop.
The most likely cause of this noise is the fuel line damper, located between the fuel supply line and the distribution rail on the engine. The purpose of this damper is to reduce the fuel pressure waves that are generated in the supply line by the simultaneous opening and closing of all four injectors.
A new damper, P/N 41 64 232, containing a spring-loaded diaphragm has been developed for use as a service measure. See PSI 10/91-0145 for the proper repair procedure.
New Special Tool: Brake Rotor Measuring Fixture - 900, 9000
A new special tool has been developed to aid in the measurement of front and rear brake rotors. This new special tool enables the technician to accurately measure a rotor for lateral run-out and thickness variation prior to resurfacing or replacement of the rotor. It can also be used for measuring the run-out of the hubs. Complete information for proper use of the tool can be found in the 900 Service Manual, Section 5:1 Brakes, M1988-91-. These instructions for use are also applicable for 9000 models.
This tool has not been designated as a required special tool. See PSI 10/91-0146 for the tool's part number and pricing information.