For 1990-2009 cars

### Circuit Description

The purpose of this code is to indicate excessive engine noise. The knock sensor can not differentiate between spark knock and other similar engine noises. When the knock sensor can not eliminate noise by retarding spark timing, DTC P0326 will be set.

### Conditions for Setting the DTC

Important: The knock circuit is continuously monitored for these parameters.

DTC P0326 will set if the PCM can not reduce engine noise by retarding timing, e.g. the engine noises probably not due to spark knock.

### Diagnostic Aids

DTC P0326 indicates excessive engine noise usually caused by something else besides spark knock. It does not indicate a faulty knock sensor circuit subsystem.

#### Possible Causes

• | Valve lifter noise

• | Belt tensioner

• | Loose bracket

• | Low octane fuel in high ambients while pulling loads

• | Piston/cylinder bore scuffed

The PCM has the ability to learn spark retard. If knock is present long enough to fill the mid, hi, and low spark compensating cells, a reduced power condition may result due to maximum spark retard. The spark compensating cells will eventually learn back (0) when the knock condition is corrected.

The spark compensating cells (hi, mid, and low spark comp) may be viewed on the scan tool spark table.

The stored spark retard (hi, mid, and low table values) are adjusted according to start-up coolant temperature.

If the coolant temperature is:

• | Below 8°C (46°F), table values are set to 0.

• | Below 56°C (133°F), table values are set to 75 percent of stored learned values.

• | Above 104°C (219°F), stored values are used.

Temperatures in between are adjusted on a percentage value.