P0333

Code

LAND ROVER P — Powertrain

Knock sensor 2 circuit high input

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 16 EN: 43 RU: 34

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Page language: EN

Causes

Short circuit in the knock sensor 2 signal wire to battery or ignition feed
Faulty or internally shorted knock sensor 2
Corroded, bent, or damaged connector terminals
Open or damaged wiring (intermittent or chafed harness)
Poor engine or sensor ground
ECM/input circuit fault or intermittent ECU internal failure

Symptoms

MIL/Check Engine light illuminated
Reduced engine performance or knock retard (loss of timing advance)
Erratic idle or surging under some conditions
Possible reduced fuel economy
Codes may be stored for knock sensor circuits and related systems

What to check

Read freeze frame and live data — note engine conditions when code set
Visually inspect sensor, wiring harness, and connector for damage, oil, heat or corrosion
Wiggle test harness/connectors with scan tool connected to see if code retriggers
Check for other related codes (other knock sensor circuits, misfires, PCM faults)
Backprobe the sensor connector and measure signal with a DMM or, preferably, an oscilloscope during cranking and running
Measure for voltage on the sensor signal circuit with the sensor disconnected to check for a short to power

Signal parameters

Knock sensors are typically piezoelectric: they produce low‑level AC pulses when detonation is present rather than a steady DC voltage
Normal idle/running: low millivolt-level pulse activity; no constant high DC voltage
A ‘high input’ fault means the ECM is seeing an abnormally high DC voltage on the sensor circuit (often near battery/ignition voltage or a persistent voltage where pulsed signal is expected)
Best diagnostic tool: oscilloscope — look for pulsed waveform during engine operation; a constant high DC level indicates a short to voltage or sensor/ECM problem

Diagnostic algorithm

Retrieve and record freeze frame, freeze-frame conditions, and any other stored codes.
Perform a thorough visual inspection of knock sensor 2, its connector, and wiring for damage, corrosion, oil contamination, heat damage, or loose mounting.
With ignition off, disconnect the sensor connector. Inspect pins for corrosion, pushed pins, or foreign material. Clean or repair connector as needed.
With the sensor disconnected, check the signal wire for a short to battery voltage using a DVOM: measure voltage between the signal wire and ground with ignition ON. A steady battery voltage or a high DC reading indicates a short to power.
Check continuity between the sensor signal pin and the ECM input pin. Also check for short to ground and short to battery along the harness. Repair any harness faults.
Backprobe the sensor connector with engine cranking/running and observe the signal. Use an oscilloscope if available: a knock sensor should produce intermittent AC pulses under load; a constant high DC level indicates a problem.
If wiring and connector check OK, swap with an identical known-good knock sensor (or fit a new sensor) to see if the code follows the sensor.
If the code persists after replacing sensor and repairing harness, test or substitute ECM if all other diagnostics point to ECM input fault (rare).
After repairs, clear codes, perform a road/test drive under load to confirm the fault does not return.
Safety note: isolate battery when performing connector repairs and secure wiring away from hot or moving components.

Likely causes

Short to battery/ignition feed on the sensor signal wire
Failed/shorted knock sensor 2
Corroded connector or poor pin contact at sensor or ECM
Damaged harness where it routes near moving parts or exhaust
Bad ground at engine block or ECM

Fault status

⚠️ Status

Knock Sensor 2 Circuit High Input — ECM detects an unexpectedly high (DC) voltage on the knock sensor 2 circuit. Possible causes include short to battery/ignition, failed sensor, wiring/connector fault, or ECM input failure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours

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P0333 — Knock sensor 2 circuit high input