Checking wiring and components with test box V.A.G 1598/42 (154-pin) — AUDI
Checking wiring and components with test box V.A.G 1598/42 (154-pin) on Audi: factory workshop procedure for engines BDW.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
🔧 Engine codes this applies to
📋 Procedure
Checking wiring and components with
test box
V.A.G 1598/42
(154-pin)
Special tools and workshop equipment required
Adapter cable
V.A.G 1598/39-1
Adapter cable
V.A.G 1598/39-2
Test box
V.A.G 1598/42
Note
The test box has 105 sockets. The connecting cable can be disconnected from the test box. This means that only the cable (and not the test box) has to be purchased for future engine control units with different types of connectors.
The smaller of the two connectors on the engine control unit has the contacts 1 to 60. The larger of the two connectors has the contacts 1 to 94.
To carry out tests on the 60-pin wiring harness connector, the adapter cable
V.A.G 1598/39-1
is connected to connector
“A”
on the test box. For components connected to 60-pin wiring harness connector
Current flow diagrams, Electrical fault finding and Fitting locations
.
To carry out tests on the 94-pin wiring harness connector, the adapter cable
V.A.G 1598/39-2
must be connected to connectors
“A”
and
“B”
on the test box. For components connected to 94-pin wiring harness connector
Current flow diagrams, Electrical fault finding and Fitting locations
.
The
test box
V.A.G 1598/42
is designed so it can be connected both to the wiring harness for the engine control unit and to the engine control unit itself at the same time.
The advantage of this is that the electronic engine control system remains fully functional when the test box is connected (for example, for measuring signals when the engine is running).
The relevant test procedure will state whether it is necessary to also connect the engine control unit to the test box.
WARNING
To prevent damage to the electronic components, select appropriate measuring range before connecting the measuring cables and observe the test requirements.
Remove engine control unit
Chapter
.
Connect
test box
V.A.G 1598/42
with
V.A.G 1598/39-1
or
V.A.G 1598/39-2
to connector on wiring harness. The earth clip on the test box must be connected to the negative battery terminal. The instructions for performing the individual tests indicate whether or not the engine control unit itself also needs to be connected to the test box.
Carry out test as described in appropriate repair procedures.
Installing engine control unit
Installation is performed in the reverse sequence.
After installation, the protective housing must be re-fitted on the control unit.
Clean threaded holes for new shear bolts to remove any residue from locking fluid. This can be done using a thread tap.
Always use new shear bolts.
Interrogate fault memory and erase if necessary. If fault memory has been erased, generate readiness code in engine control unit using
“Guided Functions”
mode of
vehicle diagnostic, testing and information system
VAS 5051B
.
Note
After completion of the Guided Fault Finding routine, the tester will attempt to erase the fault memories of all control units. If this is not successful, the remaining fault(s) registered in the memories must be rectified until all fault entries can be erased.
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.