DSGB_4_life

Ok im not really sure if im in the right place to ask this question but i had my engine light come on awhile ago and i changed my knock sensors front and back and then once i got it all put back together the light came back on saying low voltage to front and back sensors?? Any ideas on what it might be?? pinched wire? bad sensors? i clear it with my programmer and after a little bit of driving it just comes back on again. Any ideas??

cherryelky305

iTrader: (2)

low voltage means that the computer is seeing out of range voltage from that sensor, so that means its getting less than .5 volts (probably 0). must be an open or some pretty bad wire between the sensor and the pcm. I think you can force this code on any sensor by unplugging it. so look to see that its plugged in and then check for cut wires.

DSGB_4_life

ok thanks for the quick response this site is GREAT.

firemech21

iTrader: (9)

I have been having the same issue. i checked all the wires, replaced the sensors twice and have not been able to fix the issue. So if you find anything out let me know.

DSGB_4_life

my inspection is up in september so i gotta get it fixed here soon. i just dont feel like taking it all back apart....AGAIN. so i think i just might pay some1 this time. but soon as i figure out what it is ill let you know.

firemech21

iTrader: (9)

i just rewired the knock sensors from the ECU back to the sensors this morning, so if that doesnt work then i guess i will replace the sensors for a third time. Its starting to **** me off. I did find a spot behind the intake near the oil pressure sending unit where the wires had melted together a bit though, so i am hoping that solves the issue.

98RedBird

iTrader: (77)

Actually, while it's a common misconception that low voltage automatically means an open, it's also very possible it could be a short. Most times when I diagnose electrical systems what I find is low circuit voltages tend to be shorts (because the voltage want to find the easiest path back to ground so it bypasses the circuit giving a low voltage code) and high system voltages tend to be opens, because voltage in a circuit will always be source voltage (usually 5V) up to the point of the open. It just depends on where in the circuit the problem lies...

But as cherry said, check your wiring from the sensors back, get out your MM and check it out, it'll probably be obvious.

GL

fuseone

im guessing short or extra resistance some where in the circuit because if it was a open it would show full voltage

firemech21

iTrader: (9)

well after the rewire yesturday i drove it again today and the light popped back up. So now i am flat out of ideas. i keep replacing the damn sensor and that doesnt work, either and now it has all new wiring so anyone else have an idea?

LQ9CHEVELLE

iTrader: (2)

Those sensors rarely go bad.....they do get wet though down in the cavity they sit in...make sure there is no moisture down there causing a short. Also, check for continuity @ the connector from the sensor jumper wire to the harness. If it is saying both sensors are bad....you definetly have a broken connector @ the jumper, or internal break / short in your harness somewhere between the connector @ the sensors, and the PCM on the knock sensor wires. The chances of BOTH sensors dying....and being relpaced....and still being dead.....is zilch. Has the computer been out of the car recently? If so could be a bent, pushed in or broken prong on the PCM, easy to do if the connectors aren't seated right when tightening down the 7mm bolts and seating the connectors. My 2 cents.....hope ya fix it!