Skoda Workshop Service and Repair Manuals

Testing Intake manifold pressure sender -G71-   Note Only use gilded contacts to repair contacts in the plug connection of the sender. Special tools and workshop equipment required t  Vehicle system tester -V.A.G 1552 - with cable -V.A.G 1551/3, 3A, 3B, 3C- t  Test box -V.A.G 1598/31- or -V.A.G 1598/22- t  Handheld multimeter, e.g. -V.A.G 1526 B- t  Measuring tool set, e.g. -V.A.G 1594 C- t  Current flow diagram Test sequence –  Connect vehicle system tester -V.A.G 1552-. Start engine and select address word 01 “Engine electronics” → Chapter. –  Select function 08 “Read measured value block” and display group number 003.

–  Read off intake manifold pressure values indicated in display field 2. Specified value: 240…420 mbar. –  Briefly open throttle valve. The intake manifold pressure value in display field 2 must increase briefly. If 91 mbar or 1254 mbar is always indicated:

Reading measured value block 3 -> 770 rpm 365mbar 11% 2°

Display	Cause	Continue test
91 mbar	Line interruption or short-circuit to earth	→ Anchor
1254 mbar	Short circuit to positive	→ Anchor

Continuation of the test if the display reads 91 mbar:

–  Disconnect the 4-pin plug connection from the intake manifold pressure sender -G71- with intake manifold temperature sender -G42/G72--arrow- (engine may stall).

–  Bridge contacts 3 + 4 of the plug connection and observe the read-out on the display. If the display jumps to 1254 mbar: –  Select function 06 “End output” and switch ignition off. –  Replace intake manifold pressure sender -G71- with intake manifold temperature sender -G42/G72- → Chapter. If the display remains at 91 mbar: –  Select function 06 “End output” and switch ignition off. –  Connect test box - V.A.G 1598/31- or -V.A.G 1598/22 - to the wiring loom of the control unit → Chapter. The engine control unit is not connected here.

–  Check wiring between the test box and the 4-pin plug for interruption according to the current flow diagram → Current flow diagrams and Fitting locations Cable resistance: max. 1.5 Ω –  Also test wire contact 4 for short-circuit to earth and to contact 1. Specified value: ∞ Ω If the lines are not found to be faulty: –  Replace engine control unit → Chapter. Continuation of the test if the display reads 1254 mbar:

–  Disconnect the 4-pin plug connection from the intake manifold pressure sender -G71- with intake manifold temperature sender -G42/G72--arrow- (engine may stall). If the display jumps to 91 mbar: –  Select function 06 “End output” and switch ignition off. –  Replace intake manifold pressure sender -G71- with intake manifold temperature sender -G42/G72- → Chapter. If the display remains at 1254 mbar: –  Select function 06 “End output” and switch ignition off. –  Unlock connector at control unit and unplug.

–  Check the wires for plug of control unit at 4-pin plug contact 4 for short-circuit to wire contact 3 as well as after positive battery. Specified value: ∞ Ω If the lines are not found to be faulty: –  Replace engine control unit → Chapter.