P0332: Knock Sensor 2 Circuit Low Input (Bank 2)

What is P0332?

The fault code P0332 is defined as “Knock Sensor 2 Circuit Low Input (Bank 2).” This diagnostic trouble code gets logged when the engine control module (ECM) receives a low input signal from the #2 knock sensor circuit.

When abnormal combustion occurs, your engine produces a pinging or knocking sound termed engine knock or spark knock.

The knock sensor 2 circuit is mounted on the engine block. It is designed to detect an engine knock or spark knock and relay that information to the engine control module. The ECM uses this information to retard timing, protecting the engine from damage.

When you have a “Knock Sensor 2 Circuit Low Input” error, the sensor output signal is lower than specified by the manufacturer. As a result, the ECM might not receive accurate signals when the air and fuel combust early, and won’t be able to adjust the ignition timing correctly.

Common symptoms

Many potential signs indicate a “Knock Sensor 2 Circuit Low Input” error.  

Here are some common P0332 DTC symptoms:  

1. An Illuminated Check Engine Light

The Check Engine Light flickering on your dashboard is the first noticeable symptom for any engine code, including DTC P0327 and P0332 (both knock sensor error codes.)

However, you’ll need an OBD2 scan tool to help determine the exact cause of the lit Check Engine Light on your dashboard. 

2. A Pinging Or Knocking Sound

If you have code P0332, the output signal from the knock sensor is too low to signal the ECM when your engine produces a pinging or knocking sound.

As such, the ECM doesn’t retard the ignition timing when the air-fuel combusts early, resulting in unresolved engine knocking while accelerating or idling.

3. Sudden Loss Of Engine Power

Your engine losing power is another common sign of a malfunctioning knock sensor or code P0332.

A faulty knock sensor may fail to report when the ignition timing is off, resulting in the spark plug igniting the air-fuel mixture late.

Due to this delay in combustion, the engine cannot fully burn the air and fuel mixture, resulting in your engine losing power.

4. An Overheated Engine

An overheated engine could result from faulty ignition timing going undetected by a bad knock sensor. However, it could also happen when you have a faulty serpentine belt or engine cooling system.

So, it’s best to get a mechanic to diagnose the issue and see if it’s due to the diagnostic trouble code P0332.

5. Increased NOx Emissions

An engine problem related to the “Knock Sensor 2 Circuit Low Input” error could damage your vehicle’s catalytic converter.

With a damaged catalytic converter, your engine cannot convert toxic pollutants into less harmful emissions, resulting in your vehicle failing the emissions test.

In some cases, increased NOx emissions could be due to a negative fuel trim caused by a bad O2 sensor. 

6. Decreased Fuel Efficiency

A problem in your vehicle’s ignition timing or fuel trim may cause your engine to burn more fuel to propel the vehicle forward, resulting in fuel consumption spikes.

While a drop in fuel efficiency could be due to fault DTC P0332, there are many other potential reasons, so you should get your vehicle checked soon.

Can I still drive?

The fault code P0332 may not pose an immediate drivability issue. That’s because the engine code gets logged when the knock sensor is offline and not when the actual engine knocking occurs.

However, if error code P0332 is left unresolved, a faulty knock sensor won’t tell your ECM there’s a problem, and this can cascade to more severe issues, including an overheated engine, decreased fuel economy, sudden loss of engine power, and increased NOx emissions.

So, if you see the Check Engine Light flashing on your dashboard, you should have your vehicle diagnosed soon.

P0332 causes

The trouble code P0332 signifies a bad sensor or a fault with one or more of the knock sensor 2 circuit components.

Here are some common code P0332 triggers:

• A defective knock sensor or knock sensor circuit
• A damaged knock sensor wire or knock sensor connector (within the knock sensor harness)
• A lean air-fuel ratio
• A malfunctioning engine cooling system or EGR system
• A faulty engine control module

Diagnosis

Multiple factors could cause the knock sensor trouble code P0332, including a bad wire, damaged wire harness, or faulty knock sensor. It’s best to have the issue diagnosed by a mechanic.

Here’s a quick overview of how an experienced mechanic would diagnose the issue:

1. Using an OBD2 scan tool, the mechanic will check if the knock sensor code P0332 or any other code is stored in the engine control module.
2. Next, they’ll clear the existing fault codes and Check Engine Light, do a test drive, and see if the Check Engine Light or the P0332 code return.
3. Then, they’ll perform a basic knock sensor test by monitoring the ignition timing with the help of the scan tool.
4. If the ignition timing is off, they’ll check the AC voltage readings from the knock sensor, ensuring they’re within the specified range.
5. They’ll also check the AC voltage data from the temperature sensor, as false readings sent to the engine control module could result in an engine knock.
6. Finally, if the Check Engine Light is still illuminated, your mechanic will use the wiring diagram to inspect the knock sensor wire and wiring harness for damages.

Possible repairs for P0332 & Costs

Here are some solutions your mechanic would use to fix the knock sensor 2 circuit low input trouble code:

• Replace the damaged wiring harness or connector
• Ensure the sensor and circuit are grounded correctly
• Replace the bad knock sensor, ensuring the engine block has no grease or rust (a common fix for a GMC Sierra)
• Repair or replace the faulty EGR or cooling system

Repair costs

The cost of repairing the knock sensor code P0332 depends on the vehicle’s make, model, and location and whether you need a new sensor, wiring, or a knock sensor connector. So, the repair cost for a Chevrolet Silverado can vary significantly from that of a GMC Sierra or Volkswagen AG vehicle.

Here are the average estimated costs, including labor charges:

• Knock sensor harness or connector: $15 to $70

• Knock sensor: $300 to $400
• Temperature sensor: $400 to $450

3 DTC P0332 FAQs

Let’s look at some common code P0332 questions and answers:

1. What Is The Key Function Of The Knock Sensor?

The knock sensor is responsible for detecting irregularities in the engine’s vibrations. It then sends a signal to the engine control module indicating an engine knock. 

2.  How Many Knock Sensors Does A Car Have?

Typically, vehicles with 4-5 cylinders have one knock sensor. Whereas vehicles with six or more cylinders usually have two knock sensors.

3. What Are The Other Fault Codes Related To The P0332 Code?

Here are seven fault codes related to the P0332 code:

• P0324: Knock Sensor Module Performance
• P0325: Knock Sensor Circuit Bank 1
• P0326: Knock Sensor Performance
• P0328: Knock Sensor Circuit High Voltage Bank 1
• P0330: Knock Sensor Circuit Bank 2
• P0331: Knock Sensor Performance
• P0333: Knock Sensor Circuit High Voltage Bank 2