I'm getting two codes for the knock sensors. P0327 and P0332. I don't think both sensors would fail at once. What should I check here? My code reader pulls up these codes, and says it is a low-voltage input. Any help here is appreciated. BTW, my engine is a 6.0

No engine problems told at all ? IS THERE?
what an easy question . RTM is what to do read the manual. on car
called service manual, pay $20 and read it online. like all techs do.

1: well the service manual covers every one of those for sure P1xxx
factory codes. 2002 year, car.
chev. 1500? 1500HD , 2500 or 3500???????? al in HD format too.
no car told but lets do 1500 only 5.3., VIN Z automatic box.
as a rule low codes are first.
140 is
HO2S Circuit Insufficient Activity Sensor 2 174 is
Fuel Trim System Lean Bank 2, humm due to above sure. 332 =
Knock Sensor (KS) Circuit Low Voltage Bank 2 so lean burns cause knock cause 174 and knocks , expected.
1133=
HO2S Insufficient Switching Bank 1 Sensor 1 oops both side fail (banks) hummmmm what can do that, sure low fuel pressure.(and loss of power)
1153 is
HO2S Insufficient Switching Bank 2 Sensor 1
P1157, is missing in my b ook(1500) or was that really P0157?????
HO2S Circuit Low Voltage Bank 2 Sensor 2 all4x O2 fail . failed, but no heater failures 02 seen.
I bet all 4 are not bad but the enigine is hyper lean fueled.

and sensor 1 is front and when it sticks lean, the fuel pressure is low (can be or all injectors are partially clogged or FPR bad.

no statement by you , LOST ENGINE POWER>?
or engine dead.
what's up doc, why are you here, scanning, just for kicks?
and PCM is loaded with old errors never reset.?????
reset them using the tool and see if some come back.
PCM 101 here. ASE. reset it.
fuel rail pressure is spec at, VIN Z engine is

(55-62?psi) VIN: (V, T,U)
the SM has 25 steps for FPR checks and injector balance tests.
the 02 sensors can not adjust for grossly wrong fuel pressure
bad fuel or clogged injectors.
or bad bad spark (plugs , boots wires bead or coil packs)
my guess is low fuel pressure but gee I can't drive it to see that./

clunch ? clutch Are those P codes ? P0327 an P0336
The knock sensor is a piezoelectric device that produces an output voltage based on mechanical engine vibration. The PCM will retard the electronic spark timing on the signal being received. The knock sensor produces an AC signal. The amplitude and signal frequency is dependent upon the knock level. During normal operation, the knock sensor system attempts to filter out all engine noise that is not caused by spark knock. The diagnostic test for DTC P0327 turns OFF all filtering during the first 20 seconds of engine run time. If a sufficient amount of noise is detected during the 20 second test, the diagnostic passes. If no noise is detected, the diagnostic fails. Since DTC P0327 is a type B code, the diagnostic must fail during 2 consecutive ignition cycles to set the DTC.
DTC P0336
The crankshaft position (CKP) sensor defines engine position by generating an electrical pulse each time it passes by a notch of the crankshaft reluctor wheel. The PCM uses crankshaft sensor pulses for fuel delivery and spark timing.

knock sensor tells the engine computer when one or more of your engine's cylinders are "knocking", that is, exploding the air/fuel mixture in a way that delivers less power and can be damaging to the engine if prolonged. The computer uses this information to tune the engine so that it doesn't knock. If your knock sensor on Bank #1 is generating a low output voltage (perhaps under 0.5V), then it will trigger a P0327 DTC. This P0327 code may show up intermittently or the Service Engine light may be lit constantly. Other knock sensor related DTC codes include P0325, P0326, P0328, P0329, P0330, P0331, P0332, P0333, and P0334.

Read more at: https://www.obd-codes.com/p0327

it can wait a little longer wouldnt leave for to long
http://www.obd-codes.com/p0327

Code P0327 indicates that the readings from the #1 Knock Sensor circuit are too low, is outside of its operational window and malfunctioning. Symptoms

• Check Engine Light will illuminate
• Engine pings on accelration
• Engine may be running hotter or colder than normal
• In rare cases, the engine may not exhibit noticeable symptoms

Common Problems That Trigger the P0327 Code

• Defective Knock Sensor
• Defective Knock Sensor Circuit or connections
• Defective EGR System
• Malfunctioning Cooling System
• Rich air/fuel ratio

Common Misdiagnosis

• Knock Sensor replaced when cause of code P0327 was a cooling system problem
• Knock Sensor replaced when cause of code P0327 was an EGR system malfunction

P0332 Knock Sensor 2 Circuit Low Input (Bank 2)
__________
car code reader

I think it not real probable that the cause of your knock sensor code is the result of bad gas. However, I suppose it IS possible. Most knock sensor codes are caused by engine mechanical problems like bad pully bearings, loose timing chains, broken valve springs, collapsed valve lifters, etc. that would cause a "knocking" or "tapping" in the engine.

The next most probable cause would be damaged knock sensor wiring. I have fixed many that have had damage from rodents getting into the engine compartment and chewing on the wires. Depending on which engine your Silverado is equipped with, the knock sensor could be mounted between the cylinder heads in the valley under the intake manifold. Mice like it under there.

Then again, it all depends on WHAT KIND of knock sensor code you are getting. For 2000 Silverado there are 3 possible knock sensor codes: P0325, P0327, P0332. The diagnostics (and possible causes) change depending on which code you have.

P0332 DTC Code - Knock Sensor 1 Circuit Low Input (Bank 2)
A knock sensor tells the engine computer when one or more of your engine's cylinders are "knocking", that is, exploding the air/fuel mixture in a way that delivers less power and can be damaging to the engine if prolonged.

The computer uses this information to tune the engine so that it doesn't knock. If your knock sensor on Bank #2 is generating a low output voltage (perhaps under 0.5V), then it will trigger a P0332 DTC. This P0332 code may show up intermittently or the Service Engine light may be lit constantly. Other knock sensor related DTC codes include P0325, P0326, P0327, P0328, P0329, P0330, P0331, P0333, and P0334.

You may notice drivability problems including fluctation engine RPM, a loss of power, and perhaps some hesitation. There may also be other symptoms.

Potential causes for a P0332 DTC include (but are not limited to):
The knock sensor is faulty and needs to be replaced
There is a wiring open/short/fault in the knock sensor circuit
The PCM/ECM has failed

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Hope this helps; just keep in mind that your feedback is important and I'll appreciate your time and consideration if you leave some testimonial comment about this answer.

Have a nice day and thanks for using FixYa.

Jose.

check your fuel cap
use prmium gas

P0327 - Knock Sensor Circuit Low Voltage
P0332 - Knock Sensor 2 Circuit Low Input (Bank 2)

Have you had the engine worked on? this looks like maybe the spark knock sensor is either disconnected or has been overtightened in the block, to check this locate the knock sensor at the base of the cylinder block just above where the oil pan bolts to the block, it is round (with a wire connector going to it) with a large hex nut configuration to pull it out, it is in the water jacket so if you do pull it drain the cooling system and the engine block, if you replace it DO NOT OVER-TIGHTEN IT! tighten to suggested torque setting in factory service manual.