Diagnostic trouble code (DTC) information

Condition

Fig 1: Identifying Knock Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

Diagnostic trouble code (DTC) ECM-3400 is stored if the engine control module (ECM) registers that the signal from the knock sensor (KS) is higher than 3. 75 V or below 1. 25 V for a couple of seconds.

Substitute Value

knock control is disabled
ignition retarded for safety reasons.

Possible Source

Signal too high:

short-circuit to supply voltage in the signal cable
open-circuit in signal cable
loose connections in connector
defective knock sensor (KS).

Signal too low:

short-circuit to ground in the signal cable
defective knock sensor (KS).

Fault symptom[s]

Poor performance due to retarded ignition.