P0330: How to Diagnose & Fix — Knock Sensor 2 Circuit (Bank 2)
5 vehicles · 4 makes · $150-$1,100 repair
How to diagnose and fix P0330: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Toyota 4Runner · 1996–2002
On the 3rd-gen 4Runner's 3.4L 5VZ-FE V6, the two knock sensors sit in the engine valley beneath the upper and lower intake manifolds, and their sub-wiring harness bakes over time. The harness insulation becomes brittle and crumbles, opening the circuit and setting P0325 (knock sensor 1 circuit) and/or P0330 (knock sensor 2 circuit). The ECU then pulls timing, hurting fuel economy and power. It is a very high-demand repair topic because the fix is buried under the intake, and because the ECU is extremely sensitive to sensor signal quality.
Common Symptoms
- Check engine light with P0325 and/or P0330
- Noticeably reduced fuel economy
- Slight loss of power / sluggish acceleration
- Brittle, crumbling wiring found under the intake manifold
- Code returns after aftermarket sensor install
How to Fix
Remove the upper and lower intake manifolds and replace BOTH knock sensors plus the knock-sensor sub-harness. Use OEM/Denso sensors only — aftermarket knock sensors very frequently fail to clear the code, forcing you to redo the whole labor-intensive job. Key parts: knock-sensor sub-harness Toyota 82219-34010; two Denso knock sensors (Denso 89615-series); new upper and lower intake manifold gaskets and a fresh coolant fill. Budget roughly $150-300 in genuine parts (harness + 2 sensors + gaskets), or ~$400-900 done at a shop given the intake teardown labor.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Toyota 82219-34010 5VZ-FE knock-sensor sub-harness
heat-aged valley sub-harness replaced during diagnosed knock-circuit repair Fitment/availability: 1996-2002 Toyota 4Runner 3.4L 5VZ-FE according to the retailer Fitment/availability: quantity control and purchase path live when reviewed
- Genuine Toyota/Denso 89615-12090 knock control sensor
current superseding sensor for a bank whose sensor is confirmed faulty Fitment/availability: 1996-2002 Toyota 4Runner 3.4L 5VZ-FE in the Toyota catalog; Denso manufacturer note; one sensor per listing and quantity must follow diagnosis F…
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Sources for this issue (3)
GMC Sierra 1500 · 2000–2006
The 4.8L, 5.3L, and 6.0L Vortec engines used in early GMT800 Sierra trucks place the knock sensors in wells beneath the intake manifold, where water can collect and corrode the sensors or harness. Owners frequently report recurring check-engine lights, timing retard, and reduced power, especially after washing the engine bay or driving in wet conditions. GM issued service information addressing knock sensor corrosion and revised sealing practices.
Common Symptoms
- check engine light
- reduced power
- poor acceleration
- intermittent spark retard
- codes return after rain or washing
- rough running under load
How to Fix
Diagnosis involves scanning for knock sensor circuit codes, checking freeze-frame data, and inspecting the sensor wells and sub-harness under the intake for moisture or corrosion. GM bulletin 02-06-04-023 calls for replacing the corroded rear-bank knock sensor, building an RTV dam around it on the valley cover to divert water, and removing the rear intake manifold foam seal; replace the front sensor and the sub-harness too if they test bad or show corrosion.
Sources for this issue (1)
Lexus ES · 1997–2003
On the 1MZ-FE V6 the two knock sensors sit in the valley between the cylinder heads, and their sub-harness bakes there under the intake manifold. The wire insulation hardens and chafes, shorting the signal wire to ground and setting P0325 (knock sensor 1 circuit) and/or P0330 (knock sensor 2 circuit). The ECU responds by pulling timing, so the car runs down on power and mileage with a permanent check engine light. The recurring forum lesson is that the harness - not the sensors - is usually the failed part: owners who replace only the sensors see the code return within days.
Common Symptoms
- Check engine light with P0325 and/or P0330
- Reduced power and sluggish acceleration from retarded timing
- Worse fuel economy
- Codes return shortly after replacing only the knock sensors
How to Fix
Replace both knock sensors AND the knock sensor sub-harness with genuine Toyota parts as a set; the intake manifold has to come off either way, so doing the harness at the same time is nearly free labor. Skipping the sub-harness is the single most common reason the code comes back. If codes persist after both, check the ECU ground straps and the connector pins for corrosion before condemning anything mechanical.
Sources for this issue (3)
Chevrolet Silverado 1500 · 2000–2006
GMC Yukon XL · 2000–2006
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P0330 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0330 mean?
P0330 stands for "Knock Sensor 2 Circuit (Bank 2)." This powertrain code means the engine computer detected a malfunction in the circuit for knock sensor 2, located on engine bank 2 (the cylinder bank not containing cylinder 1). The knock sensor listens for engine 'knock' or 'ping' (abnormal combustion) and lets the computer retard ignition timing to prevent engine damage. This code indicates an electrical/circuit problem with the sensor signal, not necessarily actual knocking. Drivability is often normal, but the engine may run with conservative timing, reducing power and economy and risking damage if real knock occurs.
What are the most common causes of P0330?
The most common causes of P0330 are: Faulty knock sensor on bank 2, Damaged or corroded knock sensor wiring/connector, Open or short in the knock sensor circuit, Loose or improperly torqued knock sensor, Engine ground or shielding issues affecting the signal, Faulty engine control module (rare). The specific cause varies by vehicle.
How much does it cost to fix P0330?
Repair costs for P0330 range from $150 to $1,100, depending on the vehicle and root cause.
Which vehicles are affected by P0330?
Au7o has documented P0330 across 5 vehicle models from 4 manufacturers: Chevrolet, GMC, Lexus, Toyota.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.