Testing slide travel potentiometer -G99 and quantity adjuster -N146 — AUDI

Testing operation

Notes:

A second mechanic is required to note the readings on the tester when the vehicle is moving.
Observe safety notes => Page
23-49
.

Connect fault reader V.A.G 1551 and select engine electronics control unit=>Page
01-2
.
Select the function "Read individual measured value" and enter Channel No. 06=>Page
01-46
.

Read individual measured value
⇒
Channel
06
Measured value
XXX
Indicated on display:

Switch on ignition.
Specification: 39 ... 441)

1)
When the ignition is switched on the display will show a value of more than 100 for a period of 30 seconds.

Start the engine.
Specification: more than 1002)

2)
If the engine does not start, the injection quantity will be increased in stages.

Allow engine to run at idling speed.
Specification: 68 ... 803)

3)
The displayed value will be higher when the engine is cold than when the engine is warm.

Take the vehicle for a test drive and accelerate at full throttle in 3rd gear from a speed of about 40 km/h.
Specification: The readout should increase steadily to between 170 and 190 at a speed of 100 km/h (3600 rpm).

Allow the vehicle to run on overrun.
Specification: 39 ... 44

Testing internal resistance

Switch off ignition.
Disconnect connector on injection pump
=>Fitting locations overview, Page
23-3
.

Set hand-held multimeter V.A.G 1526 to resistance measuring range and connect to the following contacts on the injection pump connector using test leads from V.A.G 1594 A:

Contact · To be tested · Specification
1 + 3 · -G99 · 0.5 ... 2.0 kω
2 + 3 · -G99 · 1.0 ... 3.0 kω
4 + 7 · -N146 · 0.4 ... 1.1 ω

If the specifications are not obtained, renew the injection pump.

Testing voltage supply

Switch off ignition.
Disconnect connector on injection pump
=>Fitting locations overview, Page
23-3
.
Set hand-held multimeter V.A.G 1526 to voltage measuring range (20 V direct current).
Switch on ignition.

Connect hand-held multimeter to the following contacts on the wiring harness connector using test leads from V.A.G 1594 A:

Contact · To be tested · Specification
2 + earth · -G99 · approx. 5 V 1)
7 + earth · -N146 · approx. battery voltage 2)

1)
If the specification is not obtained, test wiring to Diesel direct injection system control unit -J248.

2)
If the specification is not obtained, check wiring using current flow diagram.

Testing wiring

Switch off ignition.
With the ignition switched off, connect test box V.A.G 1598 A to connector for engine control unit but not to the control unit itself (control unit remains disconnected) using adapter V.A.G 1598/5=>Page
23-46
.
Disconnect connector on injection pump
=>Fitting locations overview, Page
23-3
.

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

To be tested · Connector for / wiring harness / Contact No. · Test box V.A.G 1598 A / Socket No.
-G99 · 1 · 21
2 · 39
3 · 14
-N146 · 4 · 2
4 · 1
7 · 15
7 · 16
7 · 17

Test all wires for short circuit to each other.
Rectify any open/short circuit as necessary.