Checking power-assisted steering pressure switch -F88 — AUDI

Special tools and workshop equipment required

V.A.G 1526 A
V.A.G 1594 A
V.A.G 1598/31
VAS 5051 with VAS 5051/1

or
V.A.G 1551 with V.A.G 1551/3 A

The power-assisted steering pressure switch is used for idling speed stabilisation on full left or right steering lock.

Test sequence

Connect vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select engine electronics control unit with "address word" 01 => Page
01-8
.
Engine must be idling.

Rapid data transfer
HELP
Select function XX
Display readout:

Enter "08" for "Read measured value block" function and confirm with Q key.

Read measured value block
Q
Enter display group number XXX
Display readout:

Enter "056" for "Display group number 056" and confirm with Q key.

Check power-assisted steering pressure switch in display zone 4.

Display zones
1 · 2 · 3 · 4
Display group 056: Idling speed stabilisation at operating temperature
Display · xxx rpm · xxx rpm · x.x % · X X X X X
Readout · Engine speed (actual) · Engine speed (specified) · Idling speed control / Torque change · Operating states
Operating range · / · 0XXXX / 1XXXX
Specification · 0XXXX / (with wheels straight ahead or slight steering angle)
1XXXX / (full steering lock or rapid movement of steering wheel)
Note · Value: / X = No significance / If display is not as described => Page 24-214

Checking switch

Pull connector off power-assisted steering pressure switch -F88 at power steering pump.

Connect multimeter to measure resistance on switch.
Start engine.
Specification: ∞ ω (no continuity)

Apply full right/left steering lock.
Specification: approx. 0 ω

If display does not change:

Replace power-assisted steering pressure switch -F88.

If display changes:

Check wiring => Page
24-215
.

Checking wiring

Connect test box V.A.G 1598/31 to engine control unit wiring harness. Actual engine control unit is not to be connected=>Page
24-12
.

Check for open circuit and short to earth/positive in the following wiring.

Connector, / contact · Test box V.A.G 1598/31, / socket
1 · 49
2 · 50

If necessary, eliminate open circuit in wiring/short circuit.