Subaru Enthusiasts Car Club of the Sierras - View Single Post

Highdesertsuby · 2011-04-23, 05:23 PM

ok, i did my homework and found a post from way back in 07 about testing knock sensors, but no information about the actual specs. Car had been throwing a cel PO0325 off and on for about 2-3 months. I pulled the old sensor off and saw the housing was cracked...bad sensor. Bought a new one, installed it and cleared the code, and now the cel comes on all the time with the same 0325 code. Got out the multimeter and got the following numbers...

1997 Impreza L 2.2
old sensor - no continuity, means it's dead
new sensor - .780 with the meter set to 200k ohms, .000 when set to 2000k ohms
voltage at knock sensor connector - 4.65v with ignition on, but not running

from what i have read, it should read a minimum of 400k ohms for the sensor and at least 2v at the connector. I'm still learning about electrical systems, so I'm not sure what these readings are supposed to be. From what i can figure out, the circuit is getting plenty of volts and signal from the ecu, but the resistance on the sensor seems way low. Can anyone verify this? Thanks in advance.

2011-04-23, 05:23 PM	#1
Highdesertsuby EJ22 Join Date: Mar 2008 Location: Reno Posts: 154 Car: 1997 Subaru Impreza L Class: n/a This is going to take crackerjack timing...	knock sensor resistance ok, i did my homework and found a post from way back in 07 about testing knock sensors, but no information about the actual specs. Car had been throwing a cel PO0325 off and on for about 2-3 months. I pulled the old sensor off and saw the housing was cracked...bad sensor. Bought a new one, installed it and cleared the code, and now the cel comes on all the time with the same 0325 code. Got out the multimeter and got the following numbers... 1997 Impreza L 2.2 old sensor - no continuity, means it's dead new sensor - .780 with the meter set to 200k ohms, .000 when set to 2000k ohms voltage at knock sensor connector - 4.65v with ignition on, but not running from what i have read, it should read a minimum of 400k ohms for the sensor and at least 2v at the connector. I'm still learning about electrical systems, so I'm not sure what these readings are supposed to be. From what i can figure out, the circuit is getting plenty of volts and signal from the ecu, but the resistance on the sensor seems way low. Can anyone verify this? Thanks in advance.