Check sender for intake manifold pressureand altitudesender — VW

The altitude sender is located in the control unit for diesel direct injection system. The intake manifold pressure sender is a separate component and is located together with the intake manifold temperature sender in a shared housing.
=>Overview of installation locations, page
23-5
.

Special tools, workshop equipment, test and measuring equipment and accessories required

Fault output device V.A.G 1551using cable V.A.G 1551/5
Barometer or turbocharger testing device V.A.G 1397/A
Testing box V.A.G 1598/30
Hand-held multimeter V.A.G 1526 or Multimeter V.A.G 1715
Measuring aids set V.A.G 1594
Current flow diagram

Testing Procedure

Connect the fault output device V.A.G 1551and use the "Address word" 01 to select the control unit for engine electronics. Here, the ignition must be on.
(Connecting fault reader and selecting engine electronics control unit => page
01-4
.)

Fast data interchange
HELP
Select function XX
Display:

Press the keys 0 and 8 for the function "Read measurement value block" and confirm the input using the Q key.

Read measurement value block
HELP
Enter display group number XXX
Display:

Press the keys 0, 1 and 0 for the "Display group number 10" and confirm the input using the Q key.
Read measured value block 10
⇒
0 mg/stroke
1027 mbar
1013 mbar
0.0 %
Compare the displays in display field 2 (altitude sender -F96) and display field 3 (sender for intake manifold pressure -G71) and the display on the turbocharger tester V.A.G 1397/A with each other.
Setpoint value: The pressures must match up
(Tolerance ±50 mbar)

Note:

You require the turbocharger tester to obtain an independent comparison value. The turbocharger tester must be set to measuring range I (absolute pressure). You can also use a barometer instead.

If the value in display field 2 deviates:

Press the ⇒key.
Press the keys 0 and 6 for the function "Quit data interchange" and confirm the input using the Q key.
Switch the ignition off.
Replace the control unit for diesel direct injection system (J248) =>page
23-61
.

If the value in display field 3 deviates:

Press the ⇒key.
Press the keys 0 and 6 for the function "Quit data interchange" and confirm the input using the Q key.
Start the engine and select function 08 "Read measured value block" again.
Press the keys 0, 1 and 0 for the "Display group number 10" and confirm the input using the Q key.
Pull out the connector for the intake manifold pressure sender.
=>Overview of installation locations, page
23-5
.
Watch the value in display field 3 (sender for intake manifold pressure).
Read measured value block 10
⇒
515 mg/H
1009 mbar
1009 mbar
0.0 %
It must drop to approx. 200 mbar briefly and then assume the value of the altitude sender (display field 2).

If the setpoint value is reached:

Replace the sender for intake manifold pressure with the sender for intake manifold temperature.

If the setpoint value is not reached:

Press the ⇒key.

Press the keys 0 and 6 for the function "Quit data interchange" and confirm the input using the Q key.
Switch the ignition off.
Connect the testing box V.A.G 1598/30 to the control unit wiring loom. The engine control unit is not connected in the process.

Check for breaks in the cables between the testing box and the connector in accordance with the Current flow diagram.
Contact 3+socket 3/14
Contact 4+socket 3/15
Cable resistance: max. 1.5 ω
Also check the cables for short-circuit among themselves, to the vehicle earth or the battery positive terminal.
Setpoint value: ∞ω

If not fault in the cables is discovered:

Replace the control unit for diesel direct injection system (J248) =>page
23-61
.