What this code means
P0330 often means the PCM may be seeing a Knock Sensor 2 circuit signal that is not where it expects it to be.
What the vehicle may do
- The MIL may illuminate.
- Spark control may be affected depending on the failure mode.
- The vehicle may have no obvious drivability complaint.
Possible fault areas
- Possible knock sensor signal circuit fault.
- Possible sensor return circuit fault.
- Possible connector or terminal concern.
- Possible knock sensor concern.
- Possible PCM-related concern after other checks are completed.
Diagnostic path
Opening and code logic
On this Ram 1500 with the 5.7 Hemi, P0330 is a Knock Sensor 2 circuit fault. In plain terms, the PCM is seeing a knock sensor signal that may be outside the range it expects. The truck may turn the MIL on, and depending on the failure, spark control can be affected. Broadly, this can involve the knock sensor signal circuit, the sensor return circuit, connector problems, the knock sensor itself, or, farther down the path, the PCM. Before diving into pin testing, start with the basic pre-diagnostic checks. The monitor gate for this code is engine speed above 2000 rpm, battery voltage between 7.5 volts and 15.8 volts, and barometric pressure above 75.2 kPa. The PCM sets the fault when the knock sensor input is above 4.8 volts, or less than 0.2 volts when engine speed is above 2000 rpm.
Confirm the fault before circuit testing
Start by reading codes in all modules and recording the related operating data. Save the scan report and the recorded data, then clear the codes. Turn the ignition off for a minimum of 10.0 seconds, turn it back on, and run the vehicle under the same type of conditions that set the code. Then read the codes again. If P0330 does not return, handle it as an intermittent condition. If it does return, move into the Knock Sensor 2 circuit checks.
Check the Knock Sensor 2 signal circuit for a short to another circuit
With the ignition off, isolate the Knock Sensor 2 signal circuit. Disconnect the PCM and every component connector that contains the circuit being tested, while leaving the in-line connectors connected at this stage. Use the wiring diagram to follow the circuit path. At the PCM harness side, connect one DVOM lead to the signal circuit, then use the other lead to check the other circuits at that connector. If a PCM harness terminal has to be accessed, use the GPEC Diagnostic 10436 adapter. With the circuit isolated, there should be no continuity between the Knock Sensor 2 signal circuit and any other circuit. If you do find continuity, repair the short between the circuits, using in-line connectors as needed to narrow the location, then verify the repair. If there is no continuity here, the stated path moves to the connection inspection. Because the later return point is not clear, pause, recheck the earlier diagnostic path, and avoid guessing your way into a branch that was not actually called for.
Open and high-resistance checks when the path calls for them
When the diagnostic path calls for the open and high-resistance checks, keep the ignition off. For the Knock Sensor 2 signal circuit, disconnect the PCM and the knock sensor connector that contains the circuit being tested, then use the wiring diagram to follow the path. Before measuring the circuit, measure the resistance of the DVOM leads themselves so you understand what the leads are adding. Connect one meter lead at the component connector and the other at the GPEC adapter, and measure the circuit. The GPEC Diagnostic Adapter can add up to 1.5 Ohms of resistance, and the PCM harness connectors should not be probed directly. The signal circuit should be below 3.0 Ohms. If it is not below 3.0 Ohms, repair the open or high resistance and verify the repair. If it is below 3.0 Ohms, make the same type of check on the K924 sensor return circuit. That return circuit should also be below 3.0 Ohms. If it is not, repair the open or high resistance and verify the repair.
Check for shorts between the signal, return, and ground
Next, with the ignition still off, isolate the circuits and check whether the Knock Sensor 2 signal circuit is shorted to the sensor return circuit. There should be no continuity between those circuits. If continuity is present, repair the short and verify the repair. If there is no continuity, continue with the signal circuit short-to-ground check. Keep the circuit isolated, connect the negative DVOM lead to a known good ground, and use the positive lead to check the Knock Sensor 2 signal circuit at the component connector. There should be no continuity between ground and the circuit being tested. If continuity is present, repair the short to ground, using the wiring diagram and any in-line connectors to isolate the location, then verify the repair. If there is no continuity to ground, continue to the sensor step.
Sensor replacement and retest when circuit checks pass
If the circuit tests have passed and the path has led you here, turn the ignition off and replace Knock Sensor 2. Reconnect the component and PCM connectors, turn the ignition on, clear the codes, then turn the ignition off for a minimum of 10.0 seconds. Turn it back on, operate the vehicle under the conditions that set the code, and read the codes again. If P0330 does not return, the faulty component repair took care of the fault, and you still verify the repair. If the code does return, move into connector and terminal checks.
Connection checks and final verification
For the connector side of the diagnosis, handle any applicable bulletins first. Then disconnect the PCM connectors, any related in-line connectors if equipped, and the related component connectors. Inspect the harness and component connectors carefully for poor seating, damaged locks, corrosion, water intrusion, seal damage, bent or overheated terminals, pushed-back terminals, spread terminals, and weak terminal tension. Repair any condition you find. Reconnect everything fully, making sure the connectors are seated and the locks are engaged. Clear the codes, test drive or operate the vehicle under the conditions that run this monitor, and read the codes again. If P0330 does not return, the wiring or connection problem has been repaired. If it does return after this path, replace and program the PCM, then verify the repair and confirm the code stays gone. The takeaway is simple: prove the code comes back, isolate the signal and return circuits correctly, protect the PCM terminals with the adapter, and do not condemn the module until the wiring, sensor path, and connections have been checked. For more diagnostic training, visit stepdiagnostics.com.
Final check
This diagnosis is mainly an electrical circuit isolation path: confirm the code, check the signal and return circuits, inspect the connections, then verify the repair.
For more guided automotive diagnostics, visit STEP Diagnostics.
