6E2–267
RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0325 KS Module Circuit
D06RW035–1
Circuit Description
The knock sensor is used to detect engine detonation,
allowing the powertrain control module (PCM) to retard
ignition control (IC) spark timing based on the knock
sensor (KS) signal being received. The knock sensor
produces an AC signal so that under a no knock condition
the signal on the KS circuit measures about 0.007 V AC.
The KS signal’s amplitude and frequency depend upon
the amount of knock being experienced. The PCM
contains a non-replaceable knock filter module called a
signal-to-noise enhancement filter (SNEF) module. This
filter module in the PCM determines whether knock is
occurring by comparing the signal level on the KS circuit
with the voltage level on the noise channel. The noise
channel allows the PCM to reject any false knock signal
by knowing the amount of normal engine mechanical
noise present. Normal engine noise varies depending on
engine speed and load. When the PCM determines that
an abnormally low noise channel voltage level is being
experienced, a DTC P0325 will set.
Conditions for Setting the DTC
f
Engine has been running for at least 30 seconds.
f
The PCM determines that its internal signal from its
knock filter module indicates a continuous knocking
condition for more than 10 seconds.
Action Taken When the DTC Sets
f
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
f
The PCM will use a “substitute” default spark retard
value of 6 degrees to minimize knock during conditions
when knock is likely to occur.
Conditions for Clearing the MIL/DTC
f
The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.
f
A history DTC P0325 will clear after 40 consecutive
warm-up cycles have occurred without a fault.
f
DTC P0325 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
f
Poor connection at PCM – Inspect the knock sensor
and PCM connectors for backed-out terminals, broken
locks, and improperly formed or damaged terminals.
f
Misrouted harness – Inspect the knock sensor harness
to ensure that it is not routed too close to high voltage
circuits such as spark plug coils.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Ensures that the fault is present.