P0330: Knock Sensor 2 Circuit

What this code means

P0330 may mean the PCM is seeing a Knock Sensor 2 circuit input that is outside the expected range.

What the vehicle may do

The MIL may illuminate.
The vehicle may change how it manages spark timing when knock sensor information is not trusted.

Possible fault areas

Possible signal circuit fault
Possible return circuit fault
Possible connector or terminal issue
Possible knock sensor issue
Possible PCM issue after circuit and connection checks

Diagnostic path

Opening context

On this 2019 through 2024 Ram 1500 Classic with the 5.7 HEMI, P0330 points us toward the Knock Sensor 2 circuit. In plain terms, the PCM is seeing a knock sensor input that may be outside the range it expects. The truck may turn the MIL on, and depending on how the PCM reacts, it can affect how confidently the system manages spark timing. The broad fault areas are possible wiring problems in the signal or return side, connector issues, the knock sensor itself, or, after the circuit and connection checks are exhausted, the PCM. Start with the basic system checks before getting into the pinpoint testing.

Monitor and set logic

Keep the monitor logic in mind before chasing the circuit. This diagnostic runs continuously once the engine speed is above 2000 rpm, battery voltage is between 7.5 volts and 15.8 volts, and barometric pressure is above 75.2 kPa. The PCM sets P0330 when the knock sensor input is above 4.8 volts, or when it is less than 0.2 volts with engine speed above 2000 rpm. Use those conditions as the operating window for trying to duplicate the fault.

Confirm whether the code is active

First, start the engine and operate or test drive the vehicle under the conditions that allow this code to run. Use the scan tool to read and record the codes. It may take a drive cycle to get the fault to show up, so try to reproduce the captured conditions from when it originally set. If P0330 is active or pending, continue with the circuit checks. If it is not active or pending, handle it as an intermittent condition instead of forcing the hard-fault path.

Check the signal circuit for short to voltage

Next, turn the ignition off and disconnect the Knock Sensor 2 connector. Turn the ignition back on and measure voltage on the K242 Knock Sensor 2 signal circuit at the knock sensor harness connector. If that voltage is above 5.2 volts, repair the K242 signal circuit for a short to voltage, then verify the repair and confirm the code stays gone. If it is not above 5.2 volts, move on to the resistance checks.

Check the signal and return circuits for opens or high resistance

For the next checks, do not probe the PCM harness connectors. Probing those terminals can damage them and create a poor terminal-to-pin connection. With the ignition off, disconnect PCM connector C2 and connect the GPEC Diagnostic 10436 adapter to the engine harness side of the PCM C2 connector. Do not connect the adapter to the PCM. Now measure resistance in the K242 Knock Sensor 2 signal circuit between the knock sensor harness connector and the adapter. If resistance is below 3.0 Ohms, the signal circuit passes this check and you continue. If it is not below 3.0 Ohms, repair the K242 signal circuit for an open or high resistance, then verify the repair and confirm the code stays gone. After that, measure the K924 Knock Sensor 2 return circuit between the knock sensor harness connector and the adapter. If that resistance is below 3.0 Ohms, continue. If it is not below 3.0 Ohms, repair the K924 return circuit for an open or high resistance, then verify the repair and confirm the code stays gone.

Check for shorts between circuits and to ground

With the harness still set up for circuit testing, check for continuity between the K242 Knock Sensor 2 signal circuit and the K924 Knock Sensor 2 return circuit at the knock sensor harness connector. If there is continuity between those two circuits, repair the short between the signal and return circuits, then verify the repair and confirm the code stays gone. If there is no continuity there, check for continuity between ground and the K242 signal circuit. If continuity to ground is present, repair the K242 signal circuit for a short to ground, then verify the repair and confirm the code stays gone. If the signal circuit is not shorted to ground, continue to the sensor retest step.

Replace Knock Sensor 2 and retest

Once the signal circuit, return circuit, circuit-to-circuit short, and short-to-ground checks have passed, replace Knock Sensor 2. Reconnect the Knock Sensor 2 connector and the PCM connectors, turn the ignition on, and erase the codes with the scan tool. Then operate the vehicle under the captured or monitored conditions that set the code and read the codes again. If P0330 is still active or pending, continue to the harness connection checks. If it does not return, the Knock Sensor 2 replacement repaired the fault, and you still finish by verifying the repair and confirming the code stays gone.

Inspect related harness connections

If the code is still active or pending after the sensor retest, disconnect all PCM connectors, any related in-line connectors if equipped, and the related component connectors. Inspect the connectors and terminals closely. Look for poor connector installation, damaged locks, corrosion, signs of water intrusion, damaged seals if equipped, bent terminals, overheating from a poor connection, pushed-back terminals, spread terminals, and poor terminal tension. Repair any conditions you find. Then reconnect the PCM connectors, any in-line connectors, and the related component connectors, making sure everything is fully seated and the locks are engaged. Erase the codes, operate or test drive the vehicle under the monitored conditions, and read the codes again. If P0330 returns at this point, replace and program the PCM, then verify the repair and confirm the code stays gone. If it does not return, the wiring or poor connection issue has been repaired, and you still complete the final verification.

Closing takeaway

The key on P0330 is to prove the Knock Sensor 2 circuit before condemning the module: confirm the fault is active, check the signal and return circuits in order, retest after the sensor step, and keep final verification separate from the pinpoint testing. For more diagnostic training, visit stepdiagnostics.com.