What this code means
P0330 means the PCM may be detecting a problem with the Knock Sensor 2 circuit signal.
What the vehicle may do
- The MIL may illuminate.
- The vehicle may have little or no noticeable drivability symptom.
- Engine operation can sometimes feel different if the PCM is reacting to a possible knock-signal problem.
Possible fault areas
- Possible Knock Sensor 2 signal circuit fault.
- Possible Knock Sensor 2 return circuit fault.
- Possible connector, terminal, corrosion, or water intrusion issue.
- Possible Knock Sensor 2 fault.
- Possible PCM involvement after circuit and connection checks support that direction.
Diagnostic path
Open and frame the fault
On this Ram 1500 with the 3.6 liter Pentastar, P0330 is a Knock Sensor 2 circuit fault. In plain terms, the PCM may be seeing the Knock Sensor 2 signal go outside the range it expects. The MIL may come on, and the truck may have little or no obvious drivability complaint, or it can act like the PCM is protecting the engine from a knock-signal problem. Broadly, think in terms of the Knock Sensor 2 signal circuit, the sensor return circuit, connector and terminal condition, the knock sensor itself, and only after the checks lead there, the PCM. Start with the basic system checks before getting into pinpoint testing.
Monitor gate and set logic
Before chasing the circuit, understand when this fault is supposed to run. The monitor is active with engine speed above 2000 rpm, battery voltage between 7.5 volts and 15.8 volts, and barometric pressure above 75.2 kPa. The code sets when the PCM sees Knock Sensor input voltage above 4.8 volts, or less than 0.2 volts with engine speed above 2000 rpm. Use those captured conditions to reproduce the failure instead of testing it cold with no context.
Confirm the code is current
First, read DTCs from all electronic control units and record the related environmental data. Save a scan report and the related recorded data for comparison. Clear the DTCs, turn the ignition off for a minimum of 10.0 seconds, then turn the ignition back on. Operate the vehicle under the same type of conditions that set the code, then read DTCs again. If P0330 does not return, treat it as an intermittent condition and inspect accordingly. If it does return, move into the circuit checks.
Check the signal circuit for voltage problems
With P0330 confirmed, check the Knock Sensor 2 K242 signal circuit for a short to voltage. Turn the ignition off, disconnect the harness connector at the component being tested, then turn the ignition on. Use the wiring path for the circuit, and measure voltage at the component harness connector with a DVOM. On a 5.0 volt signal or reference circuit, voltage should be between approximately 4.8 and 5.2 volts. If the measured voltage is above 5.2 volts, isolate the signal circuit and check whether it is shorted to another circuit at the PCM harness connector. If it is not above 5.2 volts, continue to the open and high-resistance checks.
Isolate the signal circuit for shorts to other circuits
When checking for a short between circuits, keep the ignition off. Isolate the K242 signal circuit by disconnecting the ECU and every component connector that contains that circuit, while leaving in-line connectors connected at this point. Connect one DVOM lead to the K242 signal circuit at the ECU harness connector, then probe the other circuits at that connector with the other lead. Use the GPEC Diagnostic 10436 adapter if a PCM harness terminal needs to be accessed. With the circuit isolated, there should be no continuity between the circuit being tested and any other circuit. If continuity is found, repair the short between the circuits that have continuity, using the wiring path and any in-line connectors to narrow down the location. Then verify the repair and confirm the code stays gone. If no continuity is found in this branch, move to the connection checks later in the path.
Check signal and return circuit resistance
Next, check the K242 signal circuit for an open or high resistance. The ignition must be off for continuity checks. Isolate the circuit by disconnecting the ECU and the component connector, then measure the resistance between the DVOM leads first so you know what the leads are adding. Measure the K242 circuit from the component harness connector to the GPEC adapter. The GPEC Diagnostic Adapter can add up to 1.5 Ohms of resistance to the circuit, and the decision point here is whether resistance is below 3.0 Ohms. If it is not below 3.0 Ohms, repair the open or high resistance in that circuit, then verify the repair and confirm the code stays gone. If it is below 3.0 Ohms, perform the same style of open or high-resistance check on the K924 sensor return circuit. Again, account for the adapter adding up to 1.5 Ohms, and use below 3.0 Ohms as the decision point. If the K924 return circuit is not below 3.0 Ohms, repair the open or high resistance, then verify the repair and confirm the code stays gone.
Check for shorts between circuits and to ground
If both circuits pass the resistance checks, isolate and check the K242 signal circuit for a short to the K924 sensor return circuit. Keep the ignition off, disconnect the ECU and every component connector that contains the circuit being tested, then check continuity between the two circuits at the component harness connector. There should be no continuity between them. If continuity is present, repair the short between the circuits, then verify the repair and confirm the code stays gone. If there is no continuity, check the K242 signal circuit for a short to ground. Again, keep the ignition off. Connect the negative DVOM lead to a known good ground and probe the K242 circuit at the component connector with the positive lead. There should be no continuity between ground and the circuit being tested. If continuity is present, repair the short to ground using the wiring path and in-line connectors to isolate the location, then verify the repair and confirm the code stays gone.
Sensor, connection checks, and final direction
If the signal circuit is not shorted to ground, replace Knock Sensor 2, reconnect the component and ECU harness connectors, turn the ignition on, clear the DTCs, and operate the vehicle under the captured or monitored conditions. Read DTCs again. If P0330 does not return, the sensor replacement repaired the fault, and you still finish by verifying the repair and confirming the code stays gone. If the code does return, inspect the related PCM, in-line, and component connections. Apply any service bulletins that fit the vehicle and concern. Disconnect the related connectors, inspect connector seating, locks, corrosion, water intrusion, weather seals, bent terminals, overheated or discolored terminals, pushed-back terminals, spread terminals, and terminal tension. Repair any connector or terminal condition found, then reconnect everything fully seated with the locks engaged. Clear the DTCs, test drive or operate the vehicle under the monitored and set conditions, and read DTCs again. If P0330 returns after those checks, replace the Powertrain Control Module, then verify the repair and confirm the code stays gone. If it does not return, complete verification. Bottom line: prove the circuit first, protect the PCM terminals while testing, and do not jump to the sensor or PCM until the signal, return, short, ground, and connection checks have led you there. For more diagnostic training, visit stepdiagnostics.com.
Final check
This code is often handled as an electrical circuit diagnosis first, with the sensor and PCM considered only after the wiring and connection path has been tested.
For more guided automotive diagnostics, visit STEP Diagnostics.
