What Does P1322 Mean?
P1322 indicates that knock sensor 3 is producing a signal above the maximum expected voltage threshold. The high-input condition could be caused by electrical interference, a sensor fault, or wiring issues. A constantly high knock sensor signal can cause the ECM to excessively retard timing, thinking detonation is always occurring.
Common Causes
30%
Knock sensor 3 internal failure generating excessive output
25%
Electromagnetic interference from nearby ignition or charging components
20%
Short to voltage in the knock sensor 3 wiring
15%
Incorrect or incompatible knock sensor installed
10%
Mechanical engine noise (bearing knock, piston slap) generating real high signals
Diagnostic Steps
1
Monitor knock sensor 3 signal level at idle compared to other knock sensors — a significantly higher baseline indicates a sensor or wiring issue.
2
Inspect the knock sensor 3 wiring for routing near ignition coils, alternator, or other EMI sources.
3
Disconnect knock sensor 3 and check if the signal voltage drops to near zero at the ECM connector — if not, the wiring has a short to voltage.
4
Verify the correct part number knock sensor is installed — wrong sensitivity rating will cause high readings.
5
Listen for unusual mechanical noises (rod knock, piston slap) that could produce legitimate high knock sensor readings.
Estimated Repair Cost
$100 - $400
Parts + labor, varies by vehicle and location
P1322 indicates that knock sensor 3 is producing a signal above the maximum expected voltage threshold. The high-input condition could be caused by electrical interference, a sensor fault, or wiring issues. A constantly high knock sensor signal can cause the ECM to excessively retard timing, thinkin...
The most common cause of P1322 (Knock Sensor 3 Circ. High Input) is: Knock sensor 3 internal failure generating excessive output
Typical repair costs for P1322 range from $100 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A falsely high knock signal causes excessive timing retard, reducing power and fuel economy. If the ECM learns to ignore the high readings, it may also miss real detonation, risking engine damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1322 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Knock Detection / Ignition Timing
Difficulty
Type
Manufacturer
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