What Does P033E Mean?
The ECM has detected an intermittent signal from knock sensor 4 on bank 2. The sensor output is cutting in and out rather than providing a continuous signal, preventing reliable knock detection on the affected cylinder group. The driver may notice intermittent timing retard causing momentary power drops during acceleration, as the ECM cannot consistently monitor for detonation.
Common Causes
35%
Loose or corroded knock sensor 4 connector with intermittent electrical contact
30%
Damaged or chafed knock sensor 4 wiring that makes and breaks contact with engine vibration
20%
Knock sensor 4 working loose from mounting point causing intermittent contact with the engine block
15%
Failing knock sensor 4 with temperature-dependent internal fault
Diagnostic Steps
1
Monitor knock sensor 4 signal on live data while performing a wiggle test on the connector and harness — any signal dropout or spike during physical disturbance pinpoints the intermittent connection.
2
Inspect the knock sensor 4 connector for corrosion, oil contamination, spread terminals, or damaged weatherpack seals that allow moisture intrusion.
3
Check the knock sensor 4 mounting bolt torque — a loose sensor will produce intermittent contact with the engine block and erratic output.
4
Trace the wiring harness from the sensor to the ECM, looking for chafing against brackets, heat shield contact points, or areas where the harness flexes with engine movement.
5
If the intermittent fault is temperature-dependent, use a heat gun to warm the sensor and connector area while monitoring the signal — this can reproduce a thermal intermittent.
Estimated Repair Cost
$100 - $400
Parts + labor, varies by vehicle and location
The ECM has detected an intermittent signal from knock sensor 4 on bank 2. The sensor output is cutting in and out rather than providing a continuous signal, preventing reliable knock detection on the affected cylinder group. The driver may notice intermittent timing retard causing momentary power d...
The most common cause of P033E (Knock Sensor 4 Circuit Intermittent (Bank 2)) is: Loose or corroded knock sensor 4 connector with intermittent electrical contact
Typical repair costs for P033E range from $100 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive for normal commuting. The intermittent nature means knock detection works some of the time. The ECM compensates with conservative timing when the signal is lost. Avoid heavy loads and high-RPM driving where knock detection is most critical for engine protection.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P033E to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Generic (SAE)
Recommended Tools
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