Open or high‑resistance wiring in the knock sensor power circuit, often due to corrosion or chafing; Poor electrical connection at the knock sensor connector or at the ECM/PCM harness; Failed knock sensor (internal short or open circuit affecting the power feed); Blown fuse or faulty relay that supplies power to the knock sensor circuit; ECM/PCM internal fault causing incorrect voltage regulation to the sensor; Damaged or shorted harness between the knock sensor and the ECM/PCM; Engine block ground strap corrosion or loose connection causing voltage drop

DTC codes / Honda codes / P1324

P1324 · HondaKnock Sensor Power Source Circuit Low Voltage

Q: What does code P1324 mean?

Knock Sensor Power Source Circuit Low Voltage. P1324 on Honda vehicles means the knock sensor control module has detected that the dedicated power feed to the knock sensor circuit is below the expected voltage threshold. The engine computer (ECM/PCM) monitors this reference voltage and sets the code when the circuit cannot sustain the required supply, which can prevent the knock sensor from accurately reporting engine detonation.

P1324 on Honda vehicles means the knock sensor control module has detected that the dedicated power feed to the knock sensor circuit is below the expected voltage threshold. The engine computer (ECM/PCM) monitors this reference voltage and sets the code when the circuit cannot sustain the required supply, which can prevent the knock sensor from accurately reporting engine detonation.

SystemPowertrain

Code typeHonda specific

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Illumination of the check engine light (CEL) on the dashboard
Often no symptoms besides the warning light, especially in mild driving conditions
Reduced engine performance or power due to the ECM retarding ignition timing as a protective measure
Slightly rougher idle or hesitation under acceleration in some cases
Poor fuel economy if the ECM defaults to a knock‑retard strategy
In rare instances, a faint audible pinging or knocking under load if the sensor signal is compromised

Common causes, most likely first

Open or high‑resistance wiring in the knock sensor power circuit, often due to corrosion or chafing
Poor electrical connection at the knock sensor connector or at the ECM/PCM harness
Failed knock sensor (internal short or open circuit affecting the power feed)
Blown fuse or faulty relay that supplies power to the knock sensor circuit
ECM/PCM internal fault causing incorrect voltage regulation to the sensor
Damaged or shorted harness between the knock sensor and the ECM/PCM
Engine block ground strap corrosion or loose connection causing voltage drop

How to diagnose and fix it

Verify battery voltage and condition, then check the fuse and relay that feed the knock sensor circuit
Inspect the knock sensor connector and harness for corrosion, loose pins, or chafed wires, and repair as needed
Measure the reference voltage at the knock sensor connector with the key on, engine off, and compare to the manufacturer’s specification
Perform a voltage drop test on the power feed wire from the ECM/PCM to the knock sensor to locate excessive resistance
Check the engine block ground straps and clean or tighten any corroded connections
If the circuit tests good, substitute a known‑good knock sensor and clear the code to see if it returns
If the code persists after all circuit and sensor checks, diagnose the ECM/PCM for internal faults following Honda service procedures

Don't Replace the Knock Sensor Yet

A low‑voltage code on the knock sensor power circuit is more often caused by a corroded connector or a chafed wire than by a failed sensor itself, so always inspect the harness before condemning the sensor.
Honda knock sensor circuits are sensitive to engine block ground integrity; a loose or corroded ground strap can create enough voltage drop to set P1324 without any visible damage to the sensor wiring.
The ECM/PCM may set P1324 even when the knock sensor is functioning perfectly, because the code monitors the supply voltage, not the sensor’s signal output, so a sensor swap alone often does not fix the issue.
Aftermarket accessories or poor previous repairs that tap into the sensor circuit can introduce resistance and trigger this code, so check for non‑factory wiring near the knock sensor harness.
On some Honda models, a failing alternator or weak battery can cause system voltage fluctuations that momentarily drop the knock sensor supply below threshold, setting a intermittent P1324 that disappears after charging system repair.

Can I keep driving with P1324?

You can usually drive the vehicle with P1324 set, but avoid heavy acceleration or towing until the fault is repaired, because the ECM may retard ignition timing and reduce power as a protective measure. If the check engine light flashes or you notice severe knocking, stop driving and seek professional diagnosis immediately.

Tools that help

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Guidance is general and written for Honda vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.