Diagnostic trouble code (DTC) information ECM-3400

Condition 

Fig 1: Identifying Knock Sensor (KS) Connector

Courtesy of VOLVO CARS OF NORTH AMERICA.

The diagnostic trouble code (DTC) is stored if the engine control module (ECM) detects that the signal from the knock sensor (KS) is higher or lower than the normal range for a certain time.

The diagnostic trouble code (DTC) can be diagnosed when the ignition is switched on.

Substitute Value 

Safety retardation of ignition advance.

Knock control is disabled.

Possible Source 

Signal too high 

• Short-circuit to supply voltage in the signal cable
• Open-circuit in the signal cable
• Contact resistance or oxidation in the connector for the knock sensor (KS)
• Damaged knock sensor (KS).

Signal too low 

• Short-circuit to ground in the signal cable
• Damaged knock sensor (KS).

Fault symptom[s] 

• Poor performance.