Checking additional signals
Checking ignition retardation during gear selection
Vehicles with automatic gearbox only
The engine control unit receives the gear selection signal via the gearbox control unit. The engine then, depending on road and engine speeds, retards the ignition briefly. This reduces the torque and gear jolt.
The V.A.G 1551 does not always recognise and display the signal for torque reduction because it is sent for an extremely short period.
Note:
To check the ignition retardation the vehicle must be driven. To do this a second person is necessary.
Warning! Secure fault reader to rear seat and operate from this position.
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
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◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
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◆ Test box V.A.G 1598/22
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◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
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◆ Adapter set V.A.G 1594
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◆ Current flow diagram
Test sequence
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‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
(Connecting fault reader and selecting engine control unit .)
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