Toyota Venza: Random Access Memory (RAM) (P0604)

Toyota Venza Service Manual / 1ar-fe Engine Control / Sfi System / Random Access Memory (RAM) (P0604)

MONITOR DESCRIPTION

The ECM continuously monitors its internal memory status. This self-check ensures that the ECM is functioning properly. It is diagnosed by internal "mirroring" of the main CPU and sub CPU to detect Random Access Memory (RAM) errors. If outputs from these CPUs are different and deviate from the standard, the ECM illuminates the MIL and stores the DTC immediately.

DTC No.	DTC Detection Condition	Trouble Area
P0604	ECM RAM error (1 trip detection logic)	ECM

MONITOR STRATEGY

Related DTCs	P0604: ECM RAM Error
Required Sensors/Components (Main)	ECM
Required Sensors/Components (Related)	None
Frequency of Operation	Continuous
Duration	6 times
MIL Operation	Immediate
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored

None

TYPICAL MALFUNCTION THRESHOLDS

RAM mirror check

Fail

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the Techstream off.
Turn the ignition switch off.
Disconnect the Techstream.
Disconnect the cable from the negative (-) battery terminal and wait for 1 minute.
Connect the cable to the negative (-) battery terminal.
Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Wait 16 seconds or more.
Enter the following menus: Powertrain / Engine / Trouble Codes.
Read the pending DTCs.
HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P0604.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.

If the judgment result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).
HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

CAUTION / NOTICE / HINT

HINT:

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.

PROCEDURE

1.	READ OUTPUT DTC (DTC P0604)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(d) Clear the DTC (See page ).

(e) Turn the ignition switch off and turn the Techstream off.

(f) Disconnect the Techstream.

(g) Disconnect the cable from the negative (-) battery terminal and wait for 1 minute.

(h) Connect the cable to the negative (-) battery terminal.

(i) Connect the Techstream to the DLC3.

(j) Turn the ignition switch to ON.

(k) Turn the Techstream on.

(l) Wait 16 seconds or more.

(m) Enter the following menus: Powertrain / Engine / Trouble Codes.

(n) Read the DTCs.

Result	Proceed to
DTC is not output	A
DTC P0604 is output	B

CHECK FOR INTERMITTENT PROBLEMS

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