Audi Workshop Service and Repair Manuals

The function of the power steering pressure switch is to stabilise the idling speed when the steering wheel is on full lock (left or right).

Test sequence

• ‒ Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 -Engine electronics" in the selection. For this purpose, the engine must be running at idling speed.

→ Display on VAS 5051:

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

→ Display on VAS 5051:

•     1 -    Enter display group
  max. input value = 255

• ‒ Enter "056" for "display group number 056" in zone -2- and confirm the entry by pressing the Q key.

→ Display on VAS 5051:

• ‒ Check the power steering pressure switch in display zone-4-.

If the display is not as described:

Check switch

• ‒ Unplug the connector for power steering pressure switch -F88 at the power steering pump.

• ‒ → Connect multimeter to switch to measure resistance.
• ‒ Start the engine.
• ‒ Specified value: ∞ω (no continuity)
• ‒ Turn the steering wheel to full lock position to right/left.
• ‒ Specified value: approx. 0 ω

If the display does not change:

• ‒ Replace the power steering pressure switch -F88.

If the display changes:

• ‒ Check the wiring connections
  .

Checking wiring

• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit; do not connect the engine control unit => Page 24-19.

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

• ‒ Rectify any open/short circuit as necessary.