Engine code
P0327: Knock sensor signal too low (bank 1)
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $0 | $0 |
| Labor: 0.5 to 1.5 hours × $125 to $175 an hour | $63 | $263 |
| Fees: shop supplies, disposal, diagnostics | $0 | $25 |
| Total, rounded | $60 | $290 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in Boston, $31.54 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
This is the range for the most common fix, diagnostic scan (check engine light). Which repair your car needs depends on a proper diagnosis.
The knock sensor listens for engine pinging through the block. The computer is getting a weaker signal from it than expected, so it may not hear real knock and can pull back timing to protect the engine.
- Safe to drive?
- Short trips only
- Most common cause
- Failed knock sensor (the sensor itself)
Short trips are usually fine, but avoid hard acceleration and towing until it is checked, since the engine may be less protected from knock.
What you may notice
- Slightly less power
- Check-engine light
- Lower fuel economy
Common causes, most likely first
- Failed knock sensor (the sensor itself)
- Damaged or corroded wiring or connector
- Loose sensor mounting bolt
- Coolant or oil leak dripping onto the sensor
Check this first
Look at the sensor connector for oil, coolant or a loose plug. Ask if the sensor bolt was torqued correctly if it was recently touched.
Other repairs that sometimes fix P0327
| Repair | Typical range, Boston |
|---|---|
| CAN bus wiring repair | $190 to $1,275 |
| ECU / engine control module replacement | $430 to $2,350 |
Before you pay
- Ask the shop what test showed this part is the cause, not just that the code appeared.
- Ask for parts and labor listed separately, and for the hours.
- Ask for a written OK before any extra work. Massachusetts rules require written authorization before repairs.
Got a quote already? Check it against the range. Want to see if your car has a recall tied to this problem? Check recalls by VIN.
Need to read a code yourself? OBD-II scanners on eBay (affiliate link, disclosure).
P0327 questions
Can a bad knock sensor hurt my engine?
If the sensor stops hearing real knock, the engine can run with too much spark advance under load, which over time can damage pistons. The computer usually holds timing back as a safeguard, and gentle driving lowers the risk further.
Why is the knock sensor so costly to replace?
On many V6 and V8 engines the sensor sits in the valley under the intake manifold. The part is cheap, but reaching it means removing other parts, so most of the bill is labor.
Will this pass an emissions test?
The lit check-engine light normally fails an emissions test, so plan on fixing it before the test is due. The repair itself does not change emissions, but the light must be off and the monitors ready.
How much does it cost to fix P0327?
The most common fix, diagnostic scan (check engine light), has a typical range of $60 to $290 in Boston. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
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Code meaning written in our own words. Some codes mean different things on different makes, so check your scan tool or manual. Not a repair shop, estimates only.