Audi A4 B8 2.0 TFSI Knock Position Sensor Code Meaning

[BradyBoi55]

Hey Audizine
I currently have a knock sensor code (P0327) Knock Sensor 1 Circuit low input. Im wondering what this means. Does it mean I have a bad sensor? If i have a bad sensor I need to replace it so my engine wont knock or ping. Any help is greatly appreciated. Thanks!

[Smac770]

Turns out the knock sensor info is in the fueling and ignition manual rather than the engine mechanical manual. Torque spec for the bolt is 20Nm. And the manual confirms the need to remove the coolant pump to replace the sensor.

Wiring diagram shows pin 3, black wire is just a ground wire for the shielding around the other two wires. The yellow and green are the signal wires.

There's no troubleshooting data in the repair manual on this device. One would assume you should be able to read a DC resistance value across pins 1 and 2 (disconnect the plug from the ECU, the multimeter will apply voltage to the wires to do the resistance measurement) of the sensor, but what is the correct value range?

There's also the question of whether there's a DC voltage applied by the ECM, and whether that's to the yellow or green wire. Some ECMs will apply a DC voltage as a circuit check. So is the DTC talking about a failure of that circuit check, or too faint an AC voltage from the piezoelectric element inside the sensor?

What values are you seeing in VCDS or OBDeleven for knock sensor voltage (ENG107232 to ...5)? I have .4xx V for 1 and 4 at warmed up idle, bit more for 3 and a bit more than that for 2, but they are all below 1 V at idle. As soon as I get on the gas, they shoot to 8.xxx V and the engine starts pulling timing. Cruising, in the 3 to 6 V range.

[Blackb8audi20]

Would that sensor cause the car not to turn on? Because I had that code now my car won’t turn on.

[lowlife89]

Would that sensor cause the car not to turn on? Because I had that code now my car won’t turn on.

But you're no longer seeing the code? Friend's car is exactly like this. Started sputtering uphill. Shut it off. Started it, running like crap. Shut it off. No longer starting. After clearing the codes, it doesn't start. No codes.

[RPMtech147]

Turns out the knock sensor info is in the fueling and ignition manual rather than the engine mechanical manual. Torque spec for the bolt is 20Nm. And the manual confirms the need to remove the coolant pump to replace the sensor.

Wiring diagram shows pin 3, black wire is just a ground wire for the shielding around the other two wires. The yellow and green are the signal wires.

There's no troubleshooting data in the repair manual on this device. One would assume you should be able to read a DC resistance value across pins 1 and 2 (disconnect the plug from the ECU, the multimeter will apply voltage to the wires to do the resistance measurement) of the sensor, but what is the correct value range?

There's also the question of whether there's a DC voltage applied by the ECM, and whether that's to the yellow or green wire. Some ECMs will apply a DC voltage as a circuit check. So is the DTC talking about a failure of that circuit check, or too faint an AC voltage from the piezoelectric element inside the sensor?

What values are you seeing in VCDS or OBDeleven for knock sensor voltage (ENG107232 to ...5)? I have .4xx V for 1 and 4 at warmed up idle, bit more for 3 and a bit more than that for 2, but they are all below 1 V at idle. As soon as I get on the gas, they shoot to 8.xxx V and the engine starts pulling timing. Cruising, in the 3 to 6 V range.

To add, the sensor creates an AC voltage, unplugged while the engine is running (due to being excited by the "knock" of combustion") The more "knock" the more AC voltage. You can the afix the sensor in a vice, smack the vice and measure the voltage. It's pretty neat. What I'm getting at, is with the engine running you should see around 1 AC volt at idle on your DVOM(meter), assuming Vag doesn't do something strange vs. other manufactures. I've never actually replaced a knock sensor on anything VAG. I believe it's the green connector to the right of the throttle body, but I'm sure someone will correct me.

[Smac770]

The measuring values are the actual volts measured from the knock sensor during each of the cylinder combustion events. Engine off values were 16.768v for me. After driving around some, idle is around 0.6-0.7v, except my cyl 2 is about double that. While cruising, I'll see 2v-7v, moves around which cylinder(s) is peaking. Apparently I didn't log any WOT pulls. Peak was in the 8s. But I've heard of people seeing values in the 10s and 20s.

There's a number of knock sensor related P032x P-codes. P0327 means it's seeing less than 0.7v when the engine rpm is over 1000 for at least a 0.5 second window.

Just log engine rpm, engine load norm, knock voltage for cyl 1-4, and coolant temp, and one other whatever you like (to keep it to 8 or less for maximum sample rate; make sure group uds is on, always for the ECM). See what you see.

Yes, it's the green plug under the backside of the intake manifold (where the 14-pin and the fuel injectors plugs are also). Apparently, if you put a resistance measurement on pins 1 and 2 of the knock sensor plug (ie, the plug to the sensor, not the wiring harness plug), it should read an open circuit, infinite resistance. If you read any resistance value, you replace it.

I wonder, if you leave the resistance measurement active and tap on the block near it, if you see resistance values pop up.

The torque of the bolt holding it to the block is important for it to function correctly. I wonder if it's loosened over time. Which would suck; don't you have to pull the coolant pump to get to it?