DESCRIPTION
The ECM continuously monitors its own internal memory status, internal circuits, and output signals transmitted to the throttle actuator. This self-check ensures that the ECM is functioning properly. If any malfunction is detected, the ECM sets the appropriate DTC and illuminates the MIL.
The ECM memory status is diagnosed by internal mirroring of the main CPU and the sub CPU to detect Random Access Memory (RAM) errors. The two CPUs also perform continuous mutual monitoring. The ECM illuminates the MIL and sets a DTC if: 1) outputs from the two CPUs are different or deviate from the standards, 2) the signals sent to the throttle actuator deviate from the standards, 3) a malfunction is found in the throttle actuator supply voltage, and 4) any other ECM malfunction is found.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
INSPECTION PROCEDURE
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
1 CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0604)
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the tester on.
(d) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(e) Read DTCs.
Result
REPLACE ECM
Ignition Switch Circuit
DESCRIPTION
The Multiplex network body ECU receives the ACC and IG signals from the
ignition switch.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 READ VALUE OF INTELLIGENT TESTER
Connect the intelligent tester to DLC3.
Turn the ignition switch ON and push the intelligent
tester main ...
Canceling the power back door system (vehicles with power
back door)
Turn the main switch off to disable
the power back door system.
Off
On*
*: The orange line at the top of the
switch indicates that the power
back door system is on.
Luggage compartment light
The luggage compartment light turns on
when the back door is opened with the
luggage ...
Power Window can be Operated After Ignition Switch is Turned OFF
Even if Operative Conditions are not Met
DESCRIPTION
The multiplex network body ECU controls power supplied to the power window
master switch and each
regulator switch continuously for 45 seconds after the ignition switch is turned
OFF unless the front doors
have been opened, so that the power window can be operated during this peri ...