Checking the Intake Manifold Temperature Sender: VW 2.8 TDI (AUH)

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

Fault output device V.A.G 1551 using cable V.A.G 1551/5
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 engine must be idling.
(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; 0and 7 for the "Display group number 007" and confirm the input using the Q key.

Read measured value block 7
⇒
15,9 5C
16.7 5C
Display:

If there is no realistic display in display field 3 or if a replacement temperature of approx. 134 °C is displayed, check the intake manifold temperature sender and the cable connections to the sender as follows:
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.
Remove the connector from the sender => Installation Points Overview, page
23-5
.
Measure resistance between contacts 1+2 on sender.

Setpoint value, see diagram

Area A shows you the resistance values for the temperature range 0...50°C; area B shows the values for the temperature range 50...100 °C.

Readout examples:

30 °C corresponds to a resistance of 1500...2000ω
80 °C corresponds to a resistance of 275...375 ω

If the setpoint value is not reached:

Replace the intake manifold temperature sender (G72).

If the setpoint value is reached:

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 1+socket 3/16
Contact 2+socket 3/29
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
.