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Ignition Failure Sensor (IFS) Circuit Malfunction
DTC
P0320
Ignition Failure Sensor (IFS) Circuit Malfunction - open or short
DESCRIPTION
With the ignition switch ON or START, voltage is applied to the ignition coil. High tension leads go to each
cylinder from the ignition coil. The ignition coil fires two spark plugs every power stroke (the cylinder under
compression and the cylinder on the exhaust stroke). Coil number one fires cylinders 1 and 4. Coil
number two fires cylinders 2 and 5. And coil number three fires cylinders 3 and 6.
The ignition power transistor, controlled by the ECU, provides a switching circuit to ground for energizing
the primary ignition coils. When a primary ignition coil is energized and deenergized, the secondary coil
produces a high voltage spike across the attached spark plugs. At the same time, the tachometer
interface (part of the ignition power transistor) provides the ECU and Transaxle Control Module (TCM)
with an RPM signal.
TROUBLESHOOTING GUIDE
Background
a. If a misfire occurs while the engine is running, the engine speed
suddenly changes.
b. ECU checks for changes in the engine speed by monitoring the
CKP signal.
Normal Operation
a. Five seconds or more have passed after the engine has started.
b. The engine speed is between 500 and 6,000 rpm.
c. The engine Coolant Temperature is higher than -10°C(14°F).
d. The intake air temperature is higher than -10°C (14°F).
e. There is no sudden acceleration/deceleration such as during a
shift change.
Abnormal Operation (a change in the rate of angular acceleration by
the crankshaft is monitored for misfire detection.)
a. A misfire has occurred more frequently than allowed during the
last 200 revolutions [when the catalyst temperature is higher
than 950°C (1,742°F)].
b. A misfire has occurred more frequently than the allowed number
of times (2%) during 1,000 motor revolutions.
CIRCUIT DIAGRAM
DTC detection condition
Diagnostic item
a. Failed ignition system part(s)
b. Poor crankshaft position sensor
signal
c. Incorrect air/fuel ratio
d. Low compression
e. Failed WTS
f. Timing belt missing teeth
g. Failed injector
h. Failed ECU
Probable cause
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