- Vehicles
- Cars
P0325
P0325 (generic OBD-II): knock sensor 1 circuit
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
The engine computer is not getting a valid signal from knock sensor 1. Without it, many engines retard ignition for safety and lose some power. Avoid heavy loads, use the fuel in the manual and take the car to a workshop.
Safety first
Stop and check this first
- Without a knock signal, avoid towing and heavy loads until the repair; the engine may have less power.
Safe checks you can perform
- Fuel and driving
- Companion knock codes
- Recent repairs
Leave these tasks to a qualified professional
- Do not attempt this professional task: Knock sensor circuit measurement
- Do not attempt this professional task: Verification under load
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Knock sensor circuit measurement
What they doThe technician measures the sensor signal with a multimeter or oscilloscope with the engine running, and the continuity and insulation of the wiring to the engine computer.
They must show youthe measured signal and wiring readings against the manufacturer's specification.
In writingwhether the wire is repaired or the sensor replaced, and the part number.
Verification under load
What they doAfter the repair, the technician drives under conditions similar to the freeze frame (warm engine under load) and confirms the code does not return.
They must show youthe code reading after the drive.
In writingthe conditions of the final test.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Fuel and driving
- Who:
- you, while driving.
- How:
- check the required octane in the manual or fuel flap, and whether you hear metallic knocking when accelerating in a high gear or notice lack of power.
- Result that matters:
- whether there is knocking or power loss and whether the fuel is the right one.
- If there is knocking or lack of power:
- avoid heavy loads and steep climbs, and book soon.
- If there are no symptoms:
- book without urgency; the code still flags a circuit fault.
- Evidence to keep:
- the fuel type used and the symptoms, with dates.
Evidence: Ford 2020-2023 gasoline OBD system operation
Companion knock codes
- Who:
- you, with a generic OBD-II reader and the car parked.
- How:
- read all codes and save the freeze frame. Note any P0327, P0328, P0330 or other knock codes.
- Result that matters:
- whether the fault affects one sensor or several.
- If several sensors fail:
- this points to something shared (connector, shared wiring or the engine computer); tell the workshop.
- If only P0325:
- this points to sensor 1 or its wire.
- Evidence to keep:
- a photo of the codes and the freeze frame.
Use the reader with the car stopped and do not clear the codes.
Evidence: Ford 2020-2023 gasoline OBD system operation
Recent repairs
- Who:
- you, going through the car's invoices.
- How:
- check whether there was recent work on the intake, the manifold or the top of the engine, where the sensor and its wire often sit.
- Result that matters:
- whether the code appeared after a repair.
- If it appeared after a job:
- this points to a disturbed connector or wire; tell the workshop that did it.
- If there was no work:
- it rules nothing out; follow the diagnosis.
- Evidence to keep:
- the invoice for the last job with its date.
Evidence: Ford 2020-2023 gasoline OBD system operation
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Vehicles
- Brand
- OBD-II genérico
- Product type
- Cars
Known code variants
- P0325
- P0325 knock sensor circuit
- P0325 OBD2
- P0325 sensor de picado
What it means
P0325 is the generic code for a fault in the knock sensor 1 circuit. The sensor picks up detonation vibration so the engine computer can adjust ignition timing. In Ford's OBD summary the check runs continuously within its conditions (warm engine under load) and sets the fault when the signal is too low for the engine speed. Ford has separate codes for circuit high and low and for severe knock with limited power. P0325 does not say whether the sensor, wire or connector has failed.
Warnings and stop conditions
- Mediumeditorial warning
Without a knock signal, avoid towing and heavy loads until the repair; the engine may have less power.
Evidence: Ford 2020-2023 gasoline OBD system operation
Symptoms and causes
Probable causes · in order
- Sensor connector or wiringPossible
A loose or corroded connector or a damaged wire leaves the signal low. It shows when wiring continuity and insulation are measured.
Evidence: Ford 2020-2023 gasoline OBD system operation
- Faulty knock sensorPossible
If the wiring is fine, the sensor may not produce a signal. It is confirmed by testing the sensor to the manufacturer's procedure.
Evidence: Ford 2020-2023 gasoline OBD system operation
- Fault with other knock codesPossible
If circuit high or low or severe knock codes appear, Ford treats them separately; they point to a different fault type and the workshop resolves them together.
Evidence: Ford 2020-2023 gasoline OBD system operation
Virtual technician
Does P0325 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Ford 2020-2023 gasoline OBD system operation
Ford Motor Company · 2023 · manual
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