LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2022 >> GR86 Base, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (3 Of 6) >> SFI System >> DTC P0604: Internal Control Module Random Access Memory (RAM) Error [11/2021 - ] >> Monitor Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Monitor Description

OUTLINE OF DIAGNOSIS 

Detect the malfunction of microcomputer (RAM).

If it is possible to write data to the whole area of RAM in the initial routine, and is possible to read the same data, it is judged as OK, and if not, NG.

EXECUTION CONDITION 

DIAGNOSIS 1

Secondary parameters Execution condition
ECM initialization RUN
DIAGNOSIS 2

Secondary parameters Execution condition
None  

GENERAL DRIVING CYCLE 

Perform the diagnosis immediately after ignition switch ON.

DIAGNOSTIC METHOD 

Judge as NG when the following conditions are established.

Judgment value (diagnosis 1) 

Malfunction Criteria Threshold Value
Written value to RAM Not equal to the reading value

Judgment value (diagnosis 2) 

Malfunction Criteria Threshold Value
Check error of error correction code Detected

Time needed for diagnosis 

2 times

Malfunction indicator light illumination 

Illuminates as soon as a malfunction occurs.