I agree that the diagnostic information from the OBDII port seems to change so I ran it a least a half dozen times, resetting each time.
For example, from the OBDII port, after reconnecting the brake pressure sensor connection, I did reset the original error code which, weirdly, initially came back as:
81 Einlassventil : vorne links (inlet valve, front left)
105 Brems Licht Schalter (brake light switch)
But then, after resetting the OBDII error, the ABS test consistently reported:
81 inlet valve, front left
(even after multiple error resets)
I'm guessing, from the pic below, is it that you shove the leads into the BACK of the brake pressure sensor while the sensor is connected to the hydro unit?
If so, this would be the suggested procedure to test a brake pressure sensor (but now my error is "inlet valve"???).
1. Turn off ignition
2. Remove the three-wire brake pressure sensor electrical connector (do not remove the sensor, just remove the connector!)
3. Check the brake pressure sensor (male prongs) for continuity with a DMM we don't know what values to expect???? but we may as well write them here
4. Turn ignition on (car not running)
5. Test brake pressure connector (female side) for 12v supply voltage
6. Turn ignition off
7. Reconnect brake pressure sensor
... here's where the test jig comes in ...
8. Stick three 1.5mm test probes into the BACK of the connected brake pressure connector in situ
9. Attach your DMM voltmeter to the power & signal wires (we need to determine which color is power, ground, and signal)
10. Turn ignition on (car idling)
11. Ask an assistant to press on the brake pedal as you measure the voltage change
12. You should see 0 volts to 5 volts corresponding to 0 to 250 bar pressure (0 to 3,626 psi) changes in the front brake lines as your assistant presses on the brake pedal from soft to firm.
How does this look for a test sequence for the brake pressure sensor?
The questions for confirmation are:
A) Is the suggestion to stick a probe into the BACK of the brake pressure sensor to measure voltage sweep in situ?
B) Does anyone have an idea what part the diagnostic message "inlet valve, left" is referring to?