Fuel And Ignition Systems - Fault Tracing

Section:
2

Group:
28

No.:
914

Date:
August 1994

Re:
Fault tracing of ignition and fuel systems

700/900 All

REFERENCE:
SYSTEM TESTER ST AND BREAK-OUT BOX REFERENCE GUIDE; SP 0314/2

GUIDE TO FAULT TRACING OF ELECTRONIC MANAGEMENT SYSTEMS WITH DIAGNOSTIC INSTRUMENTS

Volvo System Tester Application Chart:

Break Out Box Application Chart:

System Tester Adaptor Part Number Update Information:

This bulletin contains a list of the electronic management systems on which fault tracing can be carried out using the Volvo System Tester (VST), or Break-out Box. The part numbers of the adapters and memory cassettes which must be used are given in each case.

The VST 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.

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 a digital multimeter that is provided 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 VST 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 VST since:

^ some signals are filtered by the VST adapters and the Break-out Box measurements will be misleading if the same adapter is used;

^ in VTB adapters, the signals (pins) are arranged in the same order as in the connector, whereas the VST 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 VST adapter.