200 Knock Sensors

[Vince Maddon <vmaddon@intergrafix.net>]

On my '89 200, late MC Motor, I am having an intermittent fault light,
after replacing it back in the dash.  The engine light will typically
come on at greater the .7 bar when the engine is warm, the conditions I
understand determine knock system operation.  It VERY seldom comes on at
below 60 MPH, but is very consistent at coming on over 70 MPH.  The code
I pull is 2144, indicating no signal from knock sensor #2.  That
initially told me that the sensor was dead or the typical wiring grief.
Using a DVM, I read voltage from the sensor when tapping on the block,
so the sensor is at least not totally dead.  The connectors seem in
excellent condition.  After checking torque, cleaning wiring connectors,
etc there was no improvement.  I then decided to switch the wiring
between sensor #1 and #2, hoping that the code would either follow the
sensor or the wiring.  Instead, I have been code free for almost 3k
miles!  I obviously have been careful with the boost during this time.
I don't understand how the ECU uses both sensor signals, so I really
don't understand these results.  I REALLY don't understand the speed
correlation?  What should I expect to pay for a knock sensor?  Any
thoughts would be appreciated.  Thanks in advance!

Vince Maddon
VMADDON@intergrafix.net

98 A4-2.8q
89 200
83 928S