Checking intake manifold pressure sender and elevation sender — VW

AHY AJT AUF AXG AXL AYC
The elevation sender is located in the Diesel direct injection system control unit. The intake manifold pressure sender is a separate component and is located together with the intake manifold temperature sender in a housing on intake manifold
=>Fitting locations overview, Page
23-5
.

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

V.A.G 1397 A Turbocharger tester
Test box V.A.G 1598/31
Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
Adapter set V.A.G 1594
Current flow diagram

Test sequence

Connect the fault reader V.A.G 1551 (V.A.G 1552) and with ignition switched on select engine electronics control unit with the "Address word" 01.
(Connecting fault reader and selecting engine electronics control unit => Page
01-4
.)

Rapid data transfer
HELP
Select function XX
Indicated on display:

Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

Read measured value block
HELP
Input display group number XXX
Indicated on display:

Press keys 0, 1 and 0 for "Display group number 10" and confirm entry with Q key.
Read measured value block 10
⇒
0 mg/H
1027 mbar
1013 mbar
0.0 %
Compare display in zone 2 (elevation sender -F96) with display in zone 3 (intake manifold pressure sender -G71) and display on turbocharger test unit V.A.G 1397/A with one another.
Specification: The pressures must be the same
(tolerance ± 30 mbar)

Note:

The turbocharger test unit is required to provide an independent figure for comparison. The turbocharger test unit must be set to measuring range I (absolute pressure). A barometer can be used instead.

If value in display zone 2 deviates:

Press the ⇒key.
Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
Switch off ignition.
Renew Diesel direct injection system control unit (J248) => Page
23-124
.

Value in display zone 3 deviates:

Press the ⇒key.
Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
Start engine and select function 08 "Read measured value block" again.
Press keys 0, 1 and 0 for "Display group number 10" and confirm entry with Q key.
Disconnect intake manifold pressure sender connector.
=>Fitting locations overview, Page
23-5
.
Observe figures in display zone 3 (intake manifold pressure sender).
Read measured value block 10
⇒
515 mg/H
1009mbar
1009 mbar
0.0 %
It must fall briefly to about 400 mbar and then assume the same value as the elevation sender (display zone 2).

If the specification is obtained:

Renew intake manifold pressure sender with intake manifold temperature sender.

If the specification is not obtained:

Press the ⇒key.
Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
Switch off ignition.

Connect test box V.A.G 1598/31 to control unit wiring harness.

Note:

Loosen left headlight to connect test box, if necessary, and place to side:

=> Electrical system; Repair group 94; Lights, Lamps, Switches exterior
Electrical system
Lights, Lamps, Switches exterior

Check wiring between test box and connector for open circuit using current flow diagram.
Contact 3+ socket 31
Contact 4+ socket 71
Wire resistance: max. 1.5 ω
Additionally check wires for short to one another, to vehicle earth and to battery positive.
Specification: ∞ω

If no fault is detected in the wiring:

Renew Diesel direct injection system control unit (J248) => Page
23-6
, item
10
.