The P2337: Cylinder 2 Above Knock Threshold code indicates that the knock sensor has detected excessive knocking or detonation in Cylinder 2. This engine knock, or “pinging,” can be caused by a malfunctioning knock sensor, incorrect ignition timing, or problems with the fuel mixture. Prolonged engine knock can lead to severe damage to engine components, making it essential to address this code promptly.
P2337 – Quick Overview
Code | Information |
---|---|
Meaning | P2337: Cylinder 2 Above Knock Threshold |
Is it serious? | Yes, excessive engine knock can cause severe engine damage, including damage to pistons, cylinder walls, and bearings. Immediate action is necessary to prevent costly repairs. |
Possible causes | – Excessive engine knock or detonation – Faulty knock sensor – Ignition timing or fuel mixture issues |
How to diagnose? | – Inspect and test the knock sensor – Check ignition timing and fuel mixture – Diagnose potential causes of engine knock |
P2337 Meaning
The P2337: Cylinder 2 Above Knock Threshold code is triggered when the knock sensor for Cylinder 2 detects knocking or pinging levels above what is considered safe for the engine. Engine knock occurs when the air-fuel mixture in the cylinder detonates prematurely, and it can lead to severe damage if left unchecked. The cause may include a faulty knock sensor, improper ignition timing, poor quality fuel, or an incorrect air-fuel mixture.
Step-by-step diagnostic guide
Action | Description | Tools Needed |
---|---|---|
Check for Other Codes | Use an OBD-II scanner to determine if other related fault codes are present. Additional codes may provide context about fuel system, ignition system, or other issues contributing to engine knock. | OBD-II Scanner |
Inspect Knock Sensor for Cylinder 2 | Visually inspect the knock sensor for Cylinder 2 for signs of damage, such as cracks, loose mounting, or issues with the sensor wiring. A damaged knock sensor may give false readings, causing this code to trigger. | Flashlight, Safety Gloves |
Test the Knock Sensor | Use a multimeter to test the resistance of the knock sensor and compare it to manufacturer specifications. Replace the sensor if the readings are out of the expected range or if it shows no response. | Multimeter |
Check Wiring and Connections | Inspect the wiring and connections to the knock sensor for signs of damage, fraying, or loose connections. Faulty wiring can interfere with accurate sensor readings, contributing to incorrect detection. | Flashlight, Multimeter |
Inspect Ignition Timing | Use a timing light to verify that the ignition timing is set correctly according to the manufacturer’s specifications. Improper timing can lead to detonation, resulting in knocking. | Timing Light |
Inspect Fuel Quality and Mixture | Ensure the fuel quality is adequate and there are no signs of contamination. Check fuel pressure using a fuel pressure gauge and verify the air-fuel mixture is within ideal limits to prevent knocking. | Fuel Pressure Gauge |
Check for Carbon Deposits | Inspect the combustion chamber and intake valves for excessive carbon deposits. Excessive buildup can cause increased compression, leading to pre-ignition and engine knock. Perform a carbon cleaning procedure if necessary. | Inspection Camera |
Verify ECM Knock Retard Function | Use a scan tool to verify whether the ECM is adjusting ignition timing in response to knock sensor signals. A malfunction in ECM response could lead to excessive knock if timing adjustments are not made correctly. | Diagnostic Scan Tool |
Replace Faulty Components if Necessary | Replace any components found to be faulty, such as the knock sensor, wiring, or ignition coil, using OEM parts to ensure proper fit and functionality. | Replacement Parts, Hand Tools |
Clear the Code and Test Drive | After repairs are completed, clear the P2337 code using an OBD-II scanner. Start the vehicle and perform a test drive under varying loads to ensure the knock does not return and the sensor reads within normal thresholds. | OBD-II Scanner, Vehicle Owner’s Manual |
Recheck for Codes | After the test drive, re-scan the vehicle to verify that the P2337 code has not returned. If the code reappears, further diagnostics may be necessary to examine ECM response or deeper engine issues. | OBD-II Scanner |

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Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)