DTC Advanced Diagnostics: P0326
DTC P0326:Knock Sensor Malfunction

General Description

The powertrain control module (PCM) monitors the knock sensor for rationality faults. The knock sensor is attached to the cylinder block. The knock sensor transforms the structure borne vibrations into electrical signals which can be evaluated by the PCM. The knock sensor signal is evaluated according to intensity and spectral information of knocking and non-knocking combustions. The diagnostic strategy is identical for all cylinders. It starts by calculating a normalized reference level of knock control based on the knock sensor’s signal. This reference signal represents the basic noise of the current cylinder being analyzed. The normalized reference level of knock control is continuously monitored against minimum rationality threshold. If the normalized reference level of knock control is a specified value for a specified time, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration
0.5 second or more
DTC Type
Two drive cycles, MIL on

Enable Conditions
Condition
Minimum
Maximum
Engine speed [Engine Speed]
1,920 rpm
–
Other
Condition in steady engine load and engine speed
[ ]: HDS Parameter

Malfunction Threshold
Either of the conditions is met for at least 30 counts:
Normalized reference voltage of the knock sensor is less than 0.2002 V - 1.2012 V*.
Normalized reference voltage of the knock sensor is greater than 13.85 V - 230 V*.

*: Depends on engine speed

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
Knock sensor loose connection or poor contact
Excessively high engine noise
Knock sensor failure

Confirmation Procedure
Operating Condition
1.
Start the engine. Hold the engine speed [Engine Speed] at 3,000 rpm without load (in neutral) until the radiator fan comes on.
2.
Drive the vehicle at an engine speed [Engine Speed] 2,000 rpm or more for at least 5 seconds.
Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.