I recently changed the timing belt on a 1991 Volvo 740, and after doing so, the check engine light came on, showing a knock sensor code on the computer. We reset the system, and hte code came back. The engine runs better than it has for a while, and nothing is noticeably different.

Has anyone experienced similar issues? Is there a simple fix to try out before replacing the knock sensor?

 

Before replacing the sensor, check the connection to the knock sensor to make sure the wires are fully pushed on the connector. I had the knock sensor code throw on my 240 after having the engine out. When I reconnected it, one of the wires had pushed out of the connector.

 

the knock sensor is really reliable, what act1292 says, check the wiring. its the flat sensor under the intake manifold, where the connector is at an angle on the side. the other 2 sensors go straight in and are round, and have the plug on the top.