Electronic Management Systems - Guide To Fault Tracing
SECTION2
GROUP
28
NO
914
DATE
Nov. 1995
RE: Ignition and fuel system diagnostics 700/900
REFERENCE: SYSTEM TESTER ST AND BREAK-OUT BOX REFERENCE GUIDE; SP 031412
This Service Bulletin replaces the earlier SB 28 914 of August 1994 which should be discarded.
Guide to fault tracing of electronic management systems with diagnostic instruments
This bulletin contains a list of the electronic management systems on which fault tracing can be carried out using the Volvo System Tester (ST), or Break-out Box. The part numbers of the adapters and memory cassettes which must be used are given in each case.
The ST is a microprocessor-based instrument for fault tracing of electronic ignition and fuel injection systems. Since the instrument may be connected while the car is being test driven, it is particularly suitable for tracing intermittent faults and also for monitoring values such as the adaptive fuel trim functions.
A new adapter and cables have been developed to connect the ST to the modified data link connector (DLC) on the 900 series from model year 1996. This allows both new and old cars to be connected.
The Break-out Box is an aid to carrying out measurements on management systems and wiring, and is used in combination with a multimeter, ohmmeter or voltmeter.
Use digital multimeter that is proved with functions such as duty cycle measurement, for example Fluke 86/88.
Note:
Many systems are reset when the supply is disconnected. For this reason, the DTCs should always be displayed before the Break-out Box adapter or ST adapter is connected between the control module and wiring.
Note:
The instruments do not replace the service manuals for fault-tracing purposes, but should be used only in conjunction with the instructions contained in the manuals.
Note:
The same adapters cannot be used for the Break-out Box and ST since:
^ some signals are filtered by the ST adapters and the Break-out Box measurements will be misleading if the same adapter is used;
^ in Break-Out Box adapters, the signals (pins) are arranged in the same order as in the connector, whereas the ST requires that the signals be arranged by type. For example, ground and battery voltage signals must always be supplied to the same pins. Neither are all of the leads connected in the ST adapter.