Checking intake manifold pressure sender -G71 — AUDI

ABP AEL
Special tools and workshop equipment required

V.A.G 1526 A
V.A.G 1594 A
V.A.G 1598 A with V.A.G 1598/5
VAS 5051 with VAS 5051/1 and
VAS 5051/2

Test requirements:

Vehicle diagnostic, testing and information system VAS 5051 connected, vehicle self-diagnosis and vehicle system "01 - Engine electronics" selected.

Test sequence

Display on VAS 5051:

Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS 5051:

1 -
Enter display group

Enter "000" for "display group number 000" in zone -2- and confirm the entry by pressing the Q key.

Display on VAS 5051:

Check readout in display zones -5-and-6-.

The readouts in display zones 5 and 6 should be matched as illustrated in the tables; slight deviations are permitted.

Examples for engine code ABP
Display zone 5 · Display zone 6
100 · 100
108 · 108
116 · 116
117 · 117
121 · 121

Examples for engine code AAT up to 2nd control unit version1)
Display zone 5 · Display zone 6
100 · 208
108 · 223
116 · 238
117 · 240
121 · 247

Examples for engine code AAT from 3rd control unit version1), AEL
Display zone 5 · Display zone 6
85 · 208
90 · 223
97 · 238
98 · 240
101 · 247

1)
Explanation of the control unit versions

=> Diesel Direct Injection and Glow Plug System (TDI, 5-cylinder); Repair group 01; Self diagnosis
Diesel Direct Injection and Glow Plug System (TDI, 5-cylinder)
Self diagnosis

Start engine and run at idling speed.
The readout in display zone 5 goes down slightly (vacuum in intake manifold)

Briefly increase the engine speed to approx. 3000 rpm and then release the accelerator pedal again.
The readout in display zone 5 increases with the boost pressure and must immediately decrease again with the engine speed.

If the readout decreases slowly or if the boost pressure is still displayed although the engine is running at idle speed again, the pressure hoses between the intake manifold and the intake manifold pressure sender are bent or blocked.

Checking power supply

Unplug connector at intake manifold pressure sender -G71.

Vehicles with engine codes ABP and AAT up to 2nd control unit version1):

Connect multimeter between contacts 1 and 3 to measure voltage.

Vehicles with engine codes AAT from 3rd control unit version1) and AEL:

Connect multimeter between contacts 2 and 3 to measure voltage.

1)
Explanation of the control unit versions

=> Diesel Direct Injection and Glow Plug System (TDI, 5-cylinder); Repair group 01; Self diagnosis
Diesel Direct Injection and Glow Plug System (TDI, 5-cylinder)
Self diagnosis

All models:

Switch the ignition on.
Specification: approx. 5 V

If specification is not attained:

Test wiring for open circuit and short to positive or earth.

Checking control signal wiring

Switch ignition off.
Remove the lower part of the right A pillar trim and the front door sill panel tread strip

=> General Body Assembly; Repair group 70
General Body Assembly

Pull back floor covering at front of right footwell (If necessary, cut open the perforated seam on the left with a knife).

Unscrew bolts -arrows- for electronics box cover.
Carefully detach upper and lower sections of cover.

Pull out cross strut -arrow 3- with attached parts.
Screw out bolts -arrow 1- and -arrow 2-.
Remove engine control unit.
Disengage retaining clip and unplug control unit connector.

Note:

Always make sure that the ignition is switched off before unplugging or fitting the connector of the control unit for diesel direct injection system.

With the ignition switched off, connect test box V.A.G 1598 A only to plug connection of the engine control unit (control unit remains disconnected) using adapter V.A.G 1598/5.

Check for open circuit and short to positive or earth in the following wiring connections:

Vehicles with engine codes ABP and AAT up to 2nd control unit version1):

Connector / Contact · Test box V.A.G 1598 A / Socket
1 · 51
2 · 54
3 · 13

Vehicles with engine code AAT from 3rd control unit version1) and AEL:

Connector / Contact · Test box V.A.G 1598 A / Socket
1 · 54
2 · 13
3 · 51

1)
Explanation of the control unit versions

=> Diesel Direct Injection and Glow Plug System (TDI, 5-cylinder); Repair group 01; Self diagnosis
Diesel Direct Injection and Glow Plug System (TDI, 5-cylinder)
Self diagnosis

Check for shorts between all the lines.
Rectify any open/short circuit as necessary.
If the wiring connection is OK, replace the engine control unit.

=> Diesel Direct Injection and Glow Plug System (TDI 5-cylinder); Repair group 23; Servicing diesel direct injection system
Diesel Direct Injection and Glow Plug System (TDI 5-cylinder)
Servicing diesel direct injection system