Pegged Oil Pressure Gauge - Page 2 - PeachParts Mercedes-Benz Forum

whunter · #16 04-01-2022, 02:08 AM

Quote:

Originally Posted by JHZR2

The odd thing is that the sensor stays pegged even with engine off key out.

I assume that it’s normal spot is down/0, not fully pegged?

Diagnostic test.

Remove the wire from the oil pressure sensor.

Place a 10 ohm resistor from ground to the wire = the gauge should drop to 0 Bar.

.

JHZR2 · #17 04-01-2022, 02:41 PM

Quote:

Originally Posted by 87tdwagen

The normal spot is down, but it still could be a bad sensor and a stuck gauge. If the sensor was bad and throws it to pegged, the needle might be stuck in that position. Try tapping the gauge cluster with the ignition off and see if the needle budges or falls to 0. If it pegs with the ignition on, but no engine running, the sensor is likely bad, or there is a wiring break in between.

I tapped a bit more and it nice and smoothly dropped to zero. As soon as the key was turned on, it pegged back at 3 and didn’t go back down until I hit it hard again…

whunter · #18 04-01-2022, 06:12 PM

Quote:

Originally Posted by JHZR2

I tapped a bit more and it nice and smoothly dropped to zero. As soon as the key was turned on, it pegged back at 3 and didn’t go back down until I hit it hard again…

That indicates an issue with the gauge.

.

87tdwagen · #19 04-03-2022, 07:57 AM

Try disconnecting the sensor and see if it still pegs. If so likely in the gauge or cluster wiring. If unplugging the sensor produces a change, test the sensor and the wiring to the sensor for a ground fault or break.