P2348 – Cylinder 13 Above Knock Threshold

System: Powertrain | Standard: ISO/SAE Controlled | Fault type: General | Location: Cylinder 13

Definition source: SAE J2012/J2012DA (industry standard)

DTC P2348 is a powertrain diagnostic trouble code indicating the control module has detected a knock event on cylinder 13 that is above a calibrated threshold. This is not a guaranteed confirmation of internal engine damage or a single failed part; it is a detection outcome based on sensor input processing and operating conditions. How the code is set, what data is stored (freeze frame), and what protections are triggered can vary by vehicle. Always verify the exact enable criteria, cylinder numbering, and test procedures in the applicable service information before replacing parts.

What Does P2348 Mean?

P2348 means Cylinder 13 Above Knock Threshold. In practical terms, the powertrain control module determined that knock intensity attributed to cylinder 13 exceeded an allowable limit during the conditions when the knock-monitoring test is active. This determination is typically based on processed signals from one or more knock sensors and related logic that assigns knock activity to a specific cylinder. SAE J2012 defines the standardized structure and naming for DTCs, while the exact monitoring strategy, thresholds, and cylinder-identification method vary by vehicle.

Quick Reference

• System: Powertrain
• Official meaning: Cylinder 13 Above Knock Threshold
• Standard: ISO/SAE controlled
• Fault type: Range/Performance
• Severity: The MIL may illuminate and the module may reduce performance to protect the engine, potentially causing noticeable drivability changes under load.

Symptoms

• MIL on: Check engine light illuminated with P2348 stored as current or pending.
• Reduced power: Lower-than-normal acceleration due to protective spark retard or torque limiting.
• Roughness: Noticeable vibration or uneven running, especially during acceleration or climbing.
• Pinging/knock noise: Audible metallic rattle under load may be present, but not always.
• Poor fuel economy: Increased consumption from retarded ignition timing and reduced efficiency.
• Hesitation: Brief stumble or flat spot during tip-in or mid-range load changes.
• Hard start: Longer crank time in some cases if related faults or adaptations are present.

Common Causes

• Wiring/connector issues: Poor pin fit, corrosion, moisture intrusion, damaged insulation, or loose connectors in the knock sensor circuit path that skew the signal the control module interprets for cylinder 13.
• Harness routing problems: Harness chafing or contact with hot or vibrating components causing intermittent shorts, opens, or induced noise that can be interpreted as knock activity.
• Knock sensor fault: A degraded or biased knock sensor (or sensor internal fault) producing an abnormally high knock signal under conditions where it should be stable.
• Incorrect sensor mounting: Improper torque, missing hardware, poor mounting surface contact, or contamination between the sensor and mounting surface altering sensor sensitivity (varies by vehicle design).
• Power/ground/reference integrity: Shared sensor grounds, reference feeds, or control module grounds with excessive resistance, creating signal offsets or noise that mimic “above threshold” detection.
• Mechanical noise sources: Abnormal mechanical noises (valvetrain, rotating assembly, accessory drive, or exhaust contact) that can be picked up as knock; must be confirmed, not assumed.
• Combustion-related conditions: Operating conditions that increase knock tendency (fuel quality issues, incorrect air/fuel delivery, cooling system performance issues, carbon buildup) can contribute, but should only be concluded after data review and testing.
• Ignition control concerns: Misfire, incorrect ignition timing control, or ignition component issues that can lead to knock-like events; verify with misfire data and related DTCs rather than guessing.
• Control module/software factors: Calibration sensitivity or control module processing issues are possible but should be considered only after sensor, wiring, and mechanical/combustion checks pass (varies by vehicle).

Diagnosis Steps

Tools that help include a scan tool capable of freeze-frame and live-data logging, a digital multimeter, back-probing leads, and basic hand tools for access and inspection. An oscilloscope and a mechanic’s stethoscope (or equivalent) can be useful for comparing knock-sensor waveform behavior to engine noise. Always consult service information for connector pinouts, test points, and the correct test procedure.

1. Confirm the DTC and capture data: Verify P2348 is present and record freeze-frame data, including engine speed, load, temperature, and operating mode. Save any available knock-related PIDs and misfire counters for later comparison.
2. Check for related DTCs first: Look for misfire, fuel trim, cooling, or other sensor DTCs that could influence knock control. Address power/ground or communication DTCs before focusing on cylinder-specific knock interpretation.
3. Clear and perform a controlled recheck: Clear codes and perform a short road test or service-bay run under similar conditions to the freeze-frame (where safe). Confirm whether P2348 resets consistently or is intermittent.
4. Visual inspection of the knock sensor circuit: Inspect the knock sensor(s) and the harness section leading to the control module for rub-through, oil saturation, heat damage, poor routing, broken retainers, or connector damage. Correct any obvious issues before deeper testing.
5. Connector and terminal checks: Disconnect relevant connectors and inspect for corrosion, spread terminals, bent pins, and moisture. Verify proper terminal tension and that seals are intact. Reconnect securely and ensure connectors are fully seated and locked.
6. Wiggle test with live data logging: With the engine running (or key on, as appropriate) monitor knock-related live data and gently manipulate the harness and connectors. Log any sudden spikes, dropouts, or erratic changes that correlate with movement to pinpoint intermittent wiring faults.
7. Power/ground integrity and voltage-drop testing: Perform voltage-drop tests on the control module grounds and any shared sensor grounds involved in the knock sensor circuit (varies by vehicle). Excessive drop indicates unwanted resistance that can bias sensor signals; repair grounds and connections as needed.
8. Circuit continuity and short checks: With power safely off as required by service information, check for opens and shorts between the knock sensor signal circuit(s) and ground or power. Also check for shorting between adjacent circuits in the same loom where chafing is suspected.
9. Sensor mounting and mechanical coupling verification: Verify correct sensor mounting condition (clean surface, correct hardware presence, correct tightening method per service information). Do not assume torque values; confirm procedure for the platform and correct any mounting issues found.
10. Evaluate mechanical noise vs. knock indication: If wiring and mounting check out, assess for abnormal mechanical noise sources that could be interpreted as knock. Use listening tools and correlate with live knock data while briefly changing engine speed/load in a controlled manner.
11. Assess combustion contributors using data: Review fuel trim, misfire counters, coolant temperature behavior, and any available knock retard/advance data. If data suggests misfire, lean operation, overheating tendencies, or timing control issues, diagnose those systems per service information before replacing parts.
12. Verify the repair with a repeatable drive cycle: After corrective action, clear codes, run the vehicle under conditions similar to the freeze-frame, and confirm P2348 does not return. Recheck for pending codes and confirm live data remains stable across the operating range.

Professional tip: Treat “above knock threshold” as a signal interpretation outcome, not proof of a single failed part. Use freeze-frame conditions and a live-data log to reproduce the event, then isolate whether the trigger is electrical (intermittent harness/ground), sensor coupling (mounting), or true engine noise/combustion behavior. A structured reproduce-and-isolate approach prevents unnecessary parts replacement.

Possible Fixes & Repair Costs

Repair cost for P2348 can vary widely because it depends on whether the issue is true knock activity, a sensor/signal problem, wiring/connector integrity, or a control/firmware factor. Confirm the root cause with testing before replacing parts.

• Repair wiring/connector issues: Restore damaged insulation, poor pin fit, corrosion, or loose connectors in the knock sensor/engine harness circuits associated with the affected cylinder bank (layout varies by vehicle).
• Address poor grounds/power feeds: Clean and secure ground points and verify power/ground integrity to modules involved in knock detection and spark control, as applicable by vehicle design.
• Replace a faulty knock sensor: Replace only if testing shows the sensor is biased, noisy, physically damaged, or out of specification per service information.
• Correct mechanical contributors to knock: If verified, address carbon buildup, incorrect spark plugs/heat range, cooling system issues, abnormal combustion chamber hot spots, or other conditions that can elevate knock tendency.
• Resolve fueling/air metering problems: If data confirms a lean condition or abnormal fueling on the affected cylinder/bank, correct intake leaks, injector issues, or related air/fuel control faults found during diagnosis.
• Update or reprogram control software: If service information indicates updated calibration changes knock detection thresholds/logic or resolves false detection, perform the approved programming procedure.

Can I Still Drive With P2348?

You may be able to drive short distances if the engine runs smoothly and there is no severe loss of power, overheating, or abnormal noise, but avoid heavy load and high RPM because sustained knock can damage the engine. If the vehicle enters reduced-power mode, misfires heavily, stalls, overheats, or any safety-related warning appears, do not continue driving and have it diagnosed.

What Happens If You Ignore P2348?

Ignoring P2348 can allow repeated operation with excessive knock activity or an incorrect knock signal. Either scenario may lead to persistent drivability issues, reduced performance and fuel economy, increased emissions, and in worst cases progressive engine damage if true knock is present and not controlled.

Last updated: February 17, 2026

Vehicles Commonly Affected by P2348

• Vehicles with high cylinder-count engines where Cylinder 13 is defined in the manufacturer’s cylinder numbering scheme.
• Applications using one or more knock sensors for closed-loop spark control and knock monitoring.
• Vehicles with cylinder-specific knock detection strategies (varies by engine management design).
• Engines with tight packaging and high underhood heat that can stress wiring insulation and connectors near the engine.
• Vehicles operated under heavy load conditions (towing, long grades, performance driving) where knock control is more active.
• Engines sensitive to fuel quality or combustion deposits where knock tendency can increase over time.
• High-mileage vehicles where harness routing wear, connector fretting, or ground degradation may develop.
• Vehicles with recent engine work where connectors, grounds, or harness routing may have been disturbed.

For a reliable repair, base any parts replacement or mechanical correction on verified test results and the vehicle’s service information, since cylinder mapping and knock detection strategy vary by vehicle.