Pressure Switch/Power Steering -F88-, Checking

Pressure Switch/Power Steering -F88-, Checking

The pressure switch for power steering is used for idle stabilization when the steering is turned to full stop (left or right).

Work sequence
- Connect VAS5051 tester, Vehicle Diagnostic, Testing and Information System VAS 5051, Connecting and Selecting Functions and select vehicle system "01 - Engine electronics". Engine must run at idle.







Display on VAS5051:
- Select diagnostic function "08 - read measured value block" in selection -1-.







Display on VAS5051:
1 - Enter display group. Max. input value = 255
- Select function "056" in button field -2- for "display group number 056" and press Q button to confirm input.







Display on VAS5051:
- Check pressure switch/power steering in display field 4.







If indications do not resemble description:
- Check switch.

Checking switch
- Disconnect harness connector at Pressure switch/power steering -F88-, at power steering pump.







- Connect multimeter at switch for resistance measurement.
- Start engine.

- Specified value: Infinity Ohms (no continuity)

- Turn steering as far to right or left as possible.

- Specified value: approx. 0 Ohms

If reading does not change:
- Replace Pressure switch/power steering -F88-.

If indication changes:
- Check wiring connections.

Checking wiring connections
- Connect VAG1598/31 test box at wiring harness to Engine Control Module (ECM) but do not connect ECM. Scan Tool Testing and Procedures







- Check following wiring connections for open circuit and short circuit to Ground (GND) and B+:

Harness connector VAG1598/31 test box
Terminal Socket
1 49
2 50

- Repair open circuit in wiring or short circuit if necessary.