CAUTION / NOTICE / HINT
PRECAUTIONS WHEN TROUBLESHOOTING
NOTICE:
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HINT:
When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.
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(a) CAN communication DTCs are output for CAN main bus and CAN branch malfunctions as well as for internal malfunctions or power source malfunctions of ECUs or sensors for systems using CAN communication. Therefore, when DTCs for internal malfunctions or power source malfunctions of corresponding systems are output at the same time as CAN communication DTCs, troubleshoot according to the internal malfunction and power source malfunction DTCs.
(b) The DLC3 inspection can only be used to detect malfunctions in the diagnosis bus (the bus which connects the DLC3 to the central gateway ECU (network gateway ECU)).
(c) An open in a branch for ECUs or sensors that are connected to the CAN main bus can be checked by performing a CAN bus check using the GTS. (This inspection is possible when all the main bus lines are normal.)
(d) In the event of communication error history in the central bus, identify the ECUs or sensors which were not communicating by analyzing the combination of stored DTCs or by performing Communication Bus Check (Detail).
(e) If a sub bus has a communication error, the gateway function equipped ECU (sub bus monitor ECU) detects it and stores DTCs related to the error.
HINT:
On the GTS, gateway function equipped ECUs display DTCs for ECUs connected to the sub bus.
(f) When an open circuit is detected, before disconnecting related connectors for inspection, push in on the connector body to check that the connector is not loose or disconnected.
(g) When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.
PROCEDURE
1. |
VEHICLE BROUGHT TO WORKSHOP |
HINT:
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2. |
CUSTOMER PROBLEM ANALYSIS |
HINT:
(a) It is useful to confirm the symptoms and the conditions in which the vehicle was operating at the time when a malfunction occurred. This helps to narrow down the malfunctioning part.
HINT:
Symptom |
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Meter warning lights |
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3. |
PRE-CHECK |
(a) Measure the auxiliary battery voltage with the ignition switch off.
Standard Voltage:
11 to 14 V
If the voltage is below 11 V, recharge or replace the auxiliary battery before proceeding to the next step.
HINT:
If the ignition switch cannot be turned to ON, measure the voltage of the auxiliary battery. If it is below 11 V, perform inspection after replacing or recharging the auxiliary battery.
NG | ![]() |
CHARGE OR REPLACE AUXILIARY BATTERY |
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4. |
CHECK GTS OPERATION |
HINT:
Read the GTS operator's manual before use.
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(a) Connect the GTS to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the GTS on.
(d) Check that the GTS and ECUs can communicate with the ignition switch ON.
HINT:
NG | ![]() |
GO TO Check CAN Communication Connection |
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5. |
BUS INSPECTION (CHECK CONNECTED ECUS AND SENSORS USING GTS) |
(a) Based on the vehicle equipment and specifications, confirm the systems that use CAN communication.
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(b) Select "CAN Bus Check" from the screen on the GTS.
CAN Bus Check(c) Observe the screen for approximately 2 minutes to check the ECUs and sensors displayed on the screen.
(d) Check for ECUs or sensors displayed as not communicating on the "Communication Bus Check" screen (indicated by a red background color or a background color that changes from red to yellow).
NOTICE:
HINT:
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Result |
Proceed to |
---|---|
No ECUs or sensors are displayed as not communicating |
A |
ECUs or sensors are displayed as not communicating |
B |
B | ![]() |
GO TO STEP 8 |
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6. |
CHECK DTC (HEALTH CHECK) |
(a) Using the GTS, perform Health Check to read current and history DTCs and record them.
NOTICE:
HINT:
If an open occurs in just one of the wires of a CAN branch line, DTCs which are not related to malfunctioning parts may be output (DTCs may be displayed randomly), or a message indicating a communication error may be displayed.
Result |
Proceed to |
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DTCs are not output. |
A |
Output DTCs are listed in the Diagnostic Trouble Code Chart for CAN Communication System. |
B |
Output DTCs are not listed in the Diagnostic Trouble Code Chart for CAN Communication System. |
C |
B | ![]() |
GO TO DTC CHART |
C | ![]() |
GO TO PERFORM DIAGNOSIS FOR RESPECTIVE SYSTEM |
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7. |
BUS INSPECTION (DETAIL) (CHECK CONNECTED ECUS AND SENSORS USING GTS) |
(a) Using the GTS, perform "Initialization".
Body Electrical > Central Gateway > Utility
Tester Display |
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Initialization |
(b) Using the GTS, display the "Communication Bus Check (Detail)" screen.
HINT:
For details on how to inspect buses using the "Communication Bus Check (Detail)" screen, refer to Description of "Communication Bus Check" Screen.
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(c) Check if ECUs or sensors with a Lost Communication Time (s) of 2 seconds or more are displayed.
Result |
Proceed to |
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No ECUs or sensors with a Lost Communication Time (s) of 2 seconds or more are displayed |
A |
ECUs or sensors with a Lost Communication Time (s) of 2 seconds or more are displayed |
B |
A | ![]() |
INSPECT FOR INTERMITTENT PROBLEMS |
B | ![]() |
GO TO DIAGNOSIS PROCEDURE FOR RESPECTIVE BUS
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8. |
CAN BUS INSPECTION (DETERMINE CAUSE OF PROBLEM SYMPTOM) |
(a) Disconnect the cable from the negative (-) auxiliary battery terminal.
(b) Measure the resistance of the CAN bus for which a malfunction is confirmed from the connector on the central gateway ECU (network gateway ECU) side.
HINT:
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Performing the bus inspection again may help in determining the suspected area.
Standard Resistance:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
CANH - CANL of a suspected bus |
Cable disconnected from negative (-) auxiliary battery terminal |
54 to 69 Ω |
CANH - body ground of a suspected bus |
Cable disconnected from negative (-) auxiliary battery terminal |
200 Ω or higher |
CANL - body ground of a suspected bus |
Cable disconnected from negative (-) auxiliary battery terminal |
200 Ω or higher |
CANH - +B of a suspected bus |
Cable disconnected from negative (-) auxiliary battery terminal |
6 kΩ or higher |
CANL - +B of a suspected bus |
Cable disconnected from negative (-) auxiliary battery terminal |
6 kΩ or higher |
OK | ![]() |
GO TO DIAGNOSIS PROCEDURE FOR RESPECTIVE COMMUNICATION STOP
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NG | ![]() |
GO TO DIAGNOSIS PROCEDURE FOR RESPECTIVE BUS
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