What causes fault code P033E?

• Most likely: Loose connection or corrosion in the knock sensor connector • Likely: Wiring harness damage (chafed insulation or short to ground) • Possible: Faulty knock sensor 4 • Rare: Incorrect sensor torque (too loose or over-tightened) • Rare: Internal PCM/ECU software fault

How do you fix fault code P033E?

STEP 1: Inspect the connector for Knock Sensor 4 for signs of corrosion or loose pins. Clean as necessary. STEP 2: Perform a resistance test on the sensor. Typical values are 100kΩ to 5MΩ depending on the manufacturer. Check the wiring harness for continuity and shorts to ground. STEP 3: Use an oscilloscope to monitor the signal in real-time. Lightly tap the cylinder block near the sensor to check for an AC voltage spike response. STEP 4: Verify that the sensor is torqued to factory specifications (usually around 20 Nm). If the sensor is found faulty, replace it with an OEM component.

Powertrain (Engine & Gearbox)Standard EOBD

P033E - Knock Sensor 4 Circuit Intermittent (Bank 2)

Q: What are the symptoms of fault code P033E?

• Check Engine Light (MIL) illuminated • Reduced engine power (ECU retards timing as a safety measure) • Decreased fuel economy • Engine hesitation during acceleration • Possible audible pinging or knocking under load

Last updated:1 February 2026

Related:Knackningssensor (Knock Sensor 4), Powertrain Control Module (PCM/ECU), Kablage och kontaktstycken, Spark Plugs and Ignition Coils

System

Powertrain (Engine & Gearbox)

Related Fault Codes

P0300

Random or Multiple Cylinder Misfire Detected

P0301

Cylinder 1 Misfire Detected

P0302

Cylinder 2 Misfire Detected

P0303

Cylinder 3 Misfire Detected

Technical Description

P033E is a generic OBD-II diagnostic trouble code indicating that the engine control module (ECM/PCM) has detected an intermittent or erratic signal from Knock Sensor 4 on Bank 2. The knock sensor is a piezoelectric sensor that monitors engine vibrations caused by pre-ignition or spark knock. If the ECU detects that the signal voltage is inconsistent or drops out temporarily, it triggers this code. The system relies on this sensor to retard ignition timing to prevent internal engine damage.

Possible Causes

Loose connection or corrosion in the knock sensor connector

Wiring harness damage (chafed insulation or short to ground)

Faulty knock sensor 4

Incorrect sensor torque (too loose or over-tightened)

Internal PCM/ECU software fault

Symptoms

Check Engine Light (MIL) illuminated

Reduced engine power (ECU retards timing as a safety measure)

Decreased fuel economy

Engine hesitation during acceleration

Possible audible pinging or knocking under load

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P033E - Knock Sensor 4 Circuit Intermittent (Bank 2)

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P033E - Knock Sensor 4 Circuit Intermittent (Bank 2)

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