Why is there no signal from Knock Sensor 1 in the 7th-generation Accord?

[DeElle]

There may be no signal from the knock sensor in the 7th-generation Accord due to a faulty sensor or poor wiring connection. Here is more relevant information: 1. Function of the knock sensor: The knock sensor transmits engine knock signals in the form of electrical signals to the electronic control module, serving as a critical basis for the control module to adjust ignition timing and prevent further knocking. 2. Types of knock sensors: There are various types of knock sensors, among which the magnetostrictive knock sensor was the earliest to be applied. It mainly consists of a magnetic core, permanent magnet, and induction coil. When the engine vibrates, the magnetic core shifts due to the vibration, altering the magnetic flux within the induction coil and generating an electromotive force. Other types, such as the piezoelectric ceramic sensor, generate a weak electrical signal when the ceramic inside is squeezed due to engine vibration. Because this signal is very weak, the connecting wires of most knock sensors are wrapped with shielded cables.

[OJeremiah]

The knock sensor 1 on this seventh-generation Accord has no signal. The common causes I've encountered are aging or damage to the sensor's internal components, as prolonged exposure to high temperatures and engine vibrations can cause its sensitive parts to fail. Another possibility is wiring issues, such as worn or broken wires from the sensor to the ECU, or loose/corroded connectors, leading to signal interruption. I've also seen cases where the sensor wasn't installed tightly or was misaligned, causing loose readings during vibrations. If the ECU's interface malfunctions or experiences voltage instability, it may also falsely indicate no signal. If not repaired promptly, undetected engine knocking can wear out pistons, increase fuel consumption, and even lead to breakdowns. It's best to visit a professional shop to read the fault codes with a diagnostic tool or check the connection points yourself using the repair manual. Regularly cleaning engine bay dust can help reduce such issues. In short, don't delay repairs too long to avoid minor problems turning into costly and time-consuming major repairs.

[Queiroz]

I previously had an issue with my seventh-generation Accord where the knock sensor 1 showed no signal, and the engine sounded strange during startup. After checking, it might have been due to water ingress and oxidation at the sensor connector, causing poor contact and signal loss; or the wiring could have been worn by nearby components, leading to a short or open circuit. At the repair shop, they used diagnostic tools and found that the sensor itself had reached the end of its lifespan and needed replacement. It's recommended to first check the sensor's location in the engine bay—on the seventh-gen Accord, it's mounted on the side of the engine, where the connection point is prone to heat exposure. You can try unplugging and reconnecting the wiring to see if it's loose, but if unsure, it's best to call a professional. Delaying the fix can lead to reduced engine power and poor driving performance.

[JasperLynn]

No signal from knock sensor 1 poses significant risks, directly impacting engine safety. Causes include sensor damage or broken wires leading to open circuits, resulting in loss of knock detection capability. Without this signal, the engine may experience excessive vibration, damaging internal components and potentially triggering warning lights that compromise driving stability. I recommend pulling over to a safe spot immediately upon noticing this warning—avoid continued driving to prevent further part damage. Conduct a quick visual inspection for oil contamination or cable breaks around the sensor, then seek professional repair for reliability. For prevention, prioritize regular engine maintenance records.