The knock sensor itself is an $80-$200 part. On most 4-cylinders it is a 30-minute job. On many GM V8s and Toyota V6s the sensor sits under the intake manifold, turning a cheap repair into a $600+ bill. Here is the real story.
OEM sensors $80-$250 each. Sets (LS V8) run $150-$300 for both plus harness.
Side-of-block sensors: 0.5-1 hour. Under-intake jobs: 3-5 hours.
| Vehicle Class | Typical Range | Notes |
|---|---|---|
| Compact car I4 (Civic, Corolla) | $150 - $300 | Easy side-of-block access |
| Sedan I4 / V6 (accessible) | $200 - $450 | Some V6s still external |
| GM Truck/SUV V8 (5.3L) | $500 - $900 | Sensors under intake |
| Toyota V6 (Tacoma, 4Runner) | $550 - $950 | Intake removal |
| Luxury / European | $600 - $1,400 | Often paired with other intake work |
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If your scan tool is showing one of these codes, this repair may be what you need.
🔬 Run a free AI diagnosis →It listens for engine knock (pre-ignition) and tells the ECU to retard timing. A bad sensor = no knock protection, weaker performance, and worse fuel economy.
Yes, but the engine runs in safe-mode (retarded timing) which hurts power and MPG. On premium-fuel engines, ignoring it long term can cause real engine damage from undetected knock.
On many V6/V8 engines, the sensor lives in the valley between the cylinder banks - under the intake manifold. The sensor is $100; getting to it is 3-5 hours of labor.
No. The code is stored permanently until the fault is fixed and the ECU is reset.
Usually yes. Aftermarket knock sensors have a high return rate, and on under-intake jobs the labor cost makes a $40 sensor a false economy.