DIAGNOSIS AND REPAIR WORKFLOW
Trouble Diagnosis Flow Chart

Trouble Diagnosis Procedure
INTERVIEW WITH CUSTOMER Interview with the customer is important to detect the root cause of CAN communication system errors and to understand vehicle condition and symptoms for proper trouble diagnosis.
Points in interview
NOTE:
- Example: Circuit between ECM and the combination meter is judged normal if the customer indicates tachometer functions normally.
Indication of the combination meter is important to detect the root cause because it is the most obvious to the customer, and it performs CAN communication with many units.

INSPECTION OF VEHICLE CONDITION Check whether the symptom is reproduced or not.
NOTE: Do not turn the ignition switch OFF or disconnect the battery cable while reproducing the error. The error may temporarily correct itself, making it difficult to determine the root cause.
CHECK OF CAN SYSTEM TYPE (HOW TO USE CAN SYSTEM TYPE SPECIFICATION CHART) Determine CAN system type based on vehicle equipment.
NOTE:
CAN System Type Specification Chart (Style A)
NOTE:
CAN system type is easily checked with the vehicle equipment identification information shown in the chart.

CAN System Type Specification Chart (Style B)
NOTE:
CAN system type is easily checked with the vehicle equipment identification information shown in the chart.

CREATE INTERVIEW SHEET
Fill out the symptom described by the customer, vehicle condition, and CAN system type on the interview sheet.
Interview Sheet (Example)

DETECT THE ROOT CAUSE CAN diagnosis function of CONSULT detects the root cause.
Trouble diagnosis
How to use this manualB2557 vehicle speed
Description
BCM receives the 2 vehicle speed signals via CAN
communication. One signal is transmitted by the "combination
meter". Another signal is transmitted by "ABS actuator and electric unit
(control unit)". BCM compares
both signals to detect the vehicle speed.
DTC Logic
DTC DETECTIO ...
Audio unit
Reference Value
TERMINAL LAYOUT
PHYSICAL VALUES
...
Emission Control System Maintenance
Drive belts*:
Check engine drive belts for wear, fraying or
cracking and for proper tension. Replace any
damaged drive belts.
Engine air filter:
Replace at specified intervals. When driving for
prolonged periods in dusty conditions,
check/replace the filter more frequently.
Engine coolant*:
...