what causes can trigger the P0326 code on a 2001 gmc sierra 1500

Question

already replaced the knock sensors and harness, and resistance is good, reference voltage is good

Answer 1

P0326 Knock sensor circuit range / performance (Bank 1 )

The knock sensor if it is not properly torque down can cause the code condition. There is 2 knock sensor

 

Here this knock sensor was water intrusion and rusted out, cleaning out the knock sensor well and replacing restored the knock sensor function. If the circuit is good and the harness is good you may just have a faulty knock sensor, New does not mean good, The knock sensor may be faulty Use TSB # 02-06-04-023A, what this this recommends is the use of silicone applied to the cover to waterproof the knock sensor sealing from water intrusion

Answer 2

P0326 - Knock Sensor Circuit Range/Performance

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