P2359 – Cylinder 8 Knock Sensor Circuit

System: Powertrain | Standard: ISO/SAE Controlled | Fault type: Circuit | Location: Cylinder 8

Definition source: SAE J2012/J2012DA (industry standard)

DTC P2359 indicates the powertrain control system has detected an electrical problem in the Cylinder 8 knock sensor circuit. A knock sensor is used by the control module to monitor engine vibration patterns so it can manage ignition timing and protect the engine. Because wiring layouts, sensor locations, and diagnostic logic vary by vehicle, the exact conditions that set P2359 (and what data the module expects to see) can differ. Use the factory service information for connector pinouts, test procedures, and specification checks before replacing parts.

What Does P2359 Mean?

P2359 – Cylinder 8 Knock Sensor Circuit means the control module has identified a circuit-related fault affecting the knock sensor circuit associated with cylinder 8. In SAE J2012 terms, this DTC points to an electrical issue in the signal path (such as wiring, connectors, sensor, or module input circuitry) rather than confirming a mechanical engine knock condition. The code definition is limited to the circuit itself; further testing is required to determine whether the problem is an open, short, excessive resistance, poor connection, or a sensor/module fault, which can vary by vehicle design.

Quick Reference

• System: Powertrain
• Official meaning: Cylinder 8 Knock Sensor Circuit
• Standard: ISO/SAE controlled
• Fault type: Circuit
• Severity: MIL illumination is possible; the module may limit ignition advance or alter engine operation, which can reduce performance and fuel economy depending on fail-safe strategy.

Symptoms

• Check engine light: MIL may illuminate and store P2359 as a current or pending fault.
• Reduced power: Noticeable loss of acceleration if the module uses a conservative timing strategy.
• Poor fuel economy: Increased consumption due to retarded ignition timing or altered engine management.
• Roughness: Light hesitation, surge, or uneven running under load depending on how the fault is handled.
• Noise sensitivity: Engine may sound louder or less refined because timing control is less optimized.
• Intermittent behavior: Symptoms may come and go with vibration, temperature changes, or moisture affecting the circuit.

Common Causes

• Connector issues at the knock sensor (cylinder 8): Loose fit, corrosion, moisture intrusion, damaged lock, or terminals pushed back.
• Harness damage in the sensor circuit: Chafing, pinched wiring, melted insulation near hot components, or broken conductors causing an open or short.
• Short-to-ground or short-to-power: Contact with metal brackets, engine components, or other circuits leading to an unintended electrical path.
• Poor ground or ground reference fault: High resistance at a shared ground point or ground splice affecting sensor signal integrity (varies by vehicle design).
• Signal circuit high resistance: Corroded splices, partially broken strands, or terminal fretting creating unstable readings.
• Knock sensor internal failure: Sensor element or internal connection fault that disrupts the circuit signal.
• ECM/PCM connector or pin damage: Bent pins, water intrusion, or poor pin tension at the control module side of the circuit.
• Incorrectly routed/strained wiring after service: Harness pulled tight, misrouted over sharp edges, or left unsecured leading to intermittent circuit faults.

Diagnosis Steps

Useful tools include a scan tool with live data and freeze-frame access, a digital multimeter, back-probing leads, and wiring diagrams/service information for correct pinouts and test procedures. An oscilloscope can help evaluate sensor circuit activity where supported. Basic hand tools for connector inspection and repair supplies for terminals and wiring are also recommended.

1. Confirm the code and capture data: Scan for P2359 and record freeze-frame data and any related DTCs. Address power/ground or communication codes first if present, as they can skew circuit diagnostics.
2. Clear and perform a brief verification run: Clear DTCs and run the engine under conditions similar to freeze-frame (as safely possible). If P2359 resets quickly, treat it as an active fault; if it does not, suspect an intermittent wiring/connector issue.
3. Locate the correct circuit and components: Using service information, identify the knock sensor associated with cylinder 8 and the exact circuit routing to the ECM/PCM (sensor connector, splices, ground points, and module pins vary by vehicle).
4. Visual inspection of harness and connectors: With ignition off, inspect the sensor connector and nearby harness for oil saturation, coolant contamination, heat damage, abrasion, or contact with sharp edges. Inspect terminal condition (corrosion, spread terminals, pushed-out pins) and connector locking integrity.
5. Wiggle test while monitoring: With the scan tool monitoring relevant knock-sensor-related data (and/or DTC status), gently wiggle the harness, sensor connector, and ECM/PCM connector area. If readings spike/drop or the code sets, isolate the section that reacts and focus on that segment for repair.
6. Check for shorts to power/ground: Key off and connectors disconnected as directed by service information, use a multimeter to check the sensor signal circuit(s) for unintended continuity to ground and to battery power. Any short indicates harness damage, pinched wiring, or connector contamination that must be corrected before further testing.
7. Check circuit continuity and resistance (end-to-end): With the sensor and ECM/PCM disconnected (where appropriate), verify continuity of the sensor circuit from the knock sensor connector to the module connector. Compare results across the circuit and flex the harness during the test to reveal intermittent opens or high resistance.
8. Perform voltage-drop testing under load: If the circuit design allows, perform voltage-drop tests across suspect connectors, splices, and ground points while the circuit is operating (or using a suitable load as specified). Excessive drop indicates high resistance at a terminal, splice, or ground connection rather than a failed sensor.
9. Evaluate sensor and mounting condition per service info: If wiring checks pass, test the knock sensor as specified (procedure varies by vehicle). Also verify the sensor is properly installed and the connector is fully seated; improper seating or damaged threads/mounting surfaces can contribute to circuit issues without proving mechanical knock.
10. Check ECM/PCM connector integrity: Inspect the module connector pins for corrosion, moisture, or poor pin tension. Ensure pin fit is correct and that any water intrusion source is corrected before reassembly.
11. Re-test and confirm repair: After repairs, clear codes, perform a road test or run cycle, and re-scan. Confirm P2359 does not return and that no new related circuit DTCs appear. If the code persists with verified wiring and sensor integrity, follow service information for module-level diagnostics.

Professional tip: Prioritize wiring and connector integrity before replacing parts. Knock sensor circuit faults are commonly caused by terminal fit, corrosion, or harness chafing that only shows up with engine vibration or heat. Use live-data logging during a controlled drive or stationary run to correlate any signal irregularities with harness movement and temperature changes, then recheck the exact area that triggers the fault.

Possible Fixes & Repair Costs

Repair costs for P2359 vary widely because the fault is circuit-related and the root cause can range from a simple connector issue to wiring repair or component replacement. Final cost depends on confirmed diagnosis, parts access, and labor time based on vehicle design.

• Repair or replace wiring: Restore damaged, chafed, pinched, or heat-affected harness sections in the cylinder 8 knock sensor circuit (use proper splices, sealing, and routing).
• Clean and secure connectors: Remove corrosion/contamination, correct moisture intrusion, ensure terminal tension, and fully seat/lock connectors at the sensor and control module as applicable.
• Correct poor grounds or power feeds: Repair shared ground points or supply circuits that affect the knock sensor circuit, including loose fasteners or high-resistance connections verified by testing.
• Replace the knock sensor: Replace only after confirming the sensor fails circuit integrity checks and the wiring/connectors test good.
• Address mechanical fitment issues: If service information calls for it, correct improper mounting/torque or contact problems that can contribute to circuit faults (procedure varies by vehicle).
• Control module connector/service actions: Repair terminal damage at the module-side connector or perform approved service actions if the circuit cannot be stabilized after wiring and sensor verification.

Can I Still Drive With P2359?

You may be able to drive short distances if the vehicle runs normally, but treat P2359 as a powertrain electrical fault that can affect how the engine manages spark timing. If you notice reduced power, significant knocking/pinging, rough running, stalling, a flashing MIL, or any brake/steering warning indicators, do not continue driving; have the circuit diagnosed and repaired to prevent engine protection strategies or drivability loss.

What Happens If You Ignore P2359?

Ignoring P2359 can lead to persistent MIL illumination, recurring drivability complaints, and the engine control system defaulting to conservative timing strategies that may reduce performance and efficiency. If the underlying circuit issue worsens (intermittent opens/shorts), it may cause more frequent fault detection, unstable operation, and increased risk of secondary damage from prolonged improper knock control behavior.

Last updated: February 15, 2026

Vehicles Commonly Affected by P2359

• V8 or multi-cylinder engines: Platforms that monitor individual cylinder knock signals and can reference cylinder 8 in diagnostics.
• Vehicles with high under-hood heat: Layouts where the knock sensor harness is exposed to heat cycling and insulation breakdown.
• Trucks and utility vehicles: Applications with longer harness runs and more vibration exposure that can stress connectors and wiring.
• Vehicles with recent engine work: Repairs where connectors may be left loose, wiring pinched, or routing altered near the sensor circuit.
• High-mileage vehicles: Age-related corrosion, brittle insulation, and terminal tension loss can contribute to circuit faults.
• Vehicles used in wet or corrosive environments: Conditions that increase the likelihood of connector contamination and wiring corrosion.
• Vehicles with previous harness repairs: Improper splices or poor sealing can introduce resistance and intermittent faults in the circuit.
• Vehicles with rodent exposure risk: Harness damage from chewing can create opens or shorts in sensor circuits.

After repairs, clear the code and complete a drive cycle while monitoring relevant live data to confirm P2359 does not return and that the knock sensor circuit remains stable under vibration and temperature changes.