P2343 indicates that the PCM has detected the vibration level from the cylinder 8 knock sensor exceeding its programmed threshold, suggesting abnormal combustion or sensor malfunction.
The sensor may be damaged, have wiring issues, or be contaminated, causing erratic voltage signals.
Corroded pins, broken wires, or poor grounding can produce false high‑vibration readings.
Worn piston rings, a stuck valve, or low compression in cylinder 8 can generate abnormal knock sensor signals.
Incorrect ignition timing or a slipped timing chain/belt can cause knock events that trigger the sensor threshold.
A malfunction in the PCM’s knock‑sensor processing circuit is possible but is the least common cause.
Replacing the PCM is rarely the correct solution. The code almost always originates from the sensor, its wiring, or a mechanical issue. Only consider the PCM after all sensor‑related checks have been exhausted and the PCM has been proven defective.
If the sensor is simply contaminated with oil or carbon, careful cleaning may restore proper operation. However, if the sensor is cracked or internally damaged, cleaning will not help and replacement is required.
The vehicle can usually be driven short distances, but prolonged operation may lead to reduced performance, higher fuel consumption, and possible engine damage if the underlying cause is severe. Repair is recommended promptly.
Yes. Abnormal combustion in cylinder 8 can increase unburned hydrocarbons and carbon monoxide, potentially causing the vehicle to fail emissions testing until the issue is resolved.