PRECAUTIONS WHEN TROUBLESHOOTING
Note
Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
If the CAN communication system is malfunctioning, check the contact pressure of the terminals in connectors, as insufficient terminal contact pressure may be the cause Click here.
Refer to Diagnosis System for the DTCs for the CAN communication system.
Refer to troubleshooting of each system if DTCs regarding the CAN communication system are not output.
Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work Click here.
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.
The DLC3 branch and V bus main bus circuits can be checked for malfunctions by inspecting at the DLC3 terminals using a electrical tester.
Note
When inspecting at the DLC3 connector, do not connect the tester directly to the terminals. Instead, connect using service wires.
Inspections for an open in an ECU or sensor branch, or inspections for buses other than the V bus cannot be performed from the DLC3.
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 the DLC3 branch and V bus CAN main wire are normal.)
If the V bus had a communication error, the probable ECU or sensor for which communication stopped can be determined using the combination of communication DTCs (DTCs that start with U) that are output.
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.
Tech Tips
On the GTS, gateway function equipped ECUs display DTCs for ECUs connected to the sub bus.
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.
When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.
VEHICLE BROUGHT TO WORKSHOP
Tech Tips
If the engine switch can be turned to on (IG) when the vehicle is brought in for repair, check for DTCs and check the illumination condition of the indicators in the combination meter assembly and the basic operation of the vehicle (such as steering operation) promptly.
Do not turn the engine switch off until the inspection of the vehicle is finished, as some fail-safe functions are canceled when the engine switch is turned off.
If the engine switch cannot be turned to on (IG) when the vehicle is brought in, measure the voltage of the battery. If the voltage is below 11 V, recharge or replace the battery before performing troubleshooting.
If the engine switch cannot be turned to on (IG) even though the battery voltage is normal, repair this malfunction before performing troubleshooting Click here.
NEXT |
CUSTOMER PROBLEM ANALYSIS
Tech Tips
When troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred.
Ask the customer if the vehicle is/was equipped with additional devices such as a theft deterrent device or monitor. (If equipped, explain the customer that the additional devices will be removed before performing troubleshooting as the malfunction cannot be checked properly.)
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.
Tech Tips
What was affected (system, part or meter warning indicators)
What happened (details of the malfunction)
When (occurrence date and time, frequency and if it recurs or not)
Under what kind of situation did the problem occur (driving and operating condition at the occurrence and weather)
Road type or condition (city, suburb, paved road, unpaved road, highway, etc.)
Return conditions (what made the vehicle return to normal. Example: engine switch was turned off)
Symptom |
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Combination meter assembly warning lights |
|
NEXT |
CHECK GTS OPERATION
Tech Tips
Read the GTS operators manual before use Click here.
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Check that the GTS and ECUs can communicate with the engine switch on (IG).
Tech Tips
If communication is impossible, the GTS screen will indicate an error.
If communication between the GTS and ECUs is impossible, either the GTS or vehicle has a malfunction.
When communication between the GTS and the vehicle is impossible, but communication is possible when the GTS is connected to another vehicle, the vehicle has the malfunction. Inspect the CANH and CANL branch lines of the DLC3 and the ECU power source circuits (in this case perform steps 7 to 9 first). In addition, check that the BAT terminal of the DLC3 receives battery voltage (11 V or more).
If communication between the GTS and ECUs is still impossible even when the GTS is connected to another vehicle, the GTS has a malfunction. Perform the self tests described in the GTS operators manual. (The GTS may be malfunctioning or its battery may be discharged.)
Result | Proceed to |
---|---|
OK (Communication between the GTS and the vehicle is possible.) | A |
OK (Communication between the GTS and the vehicle is impossible but communication is possible when connected to another vehicle.) | B |
NG (Communication is not possible between the GTS and the vehicle, nor between the GTS and another vehicle.) | C |
B |
Go to step 7 |
C |
Refer to GTS operator's manual |
A |
CHECK DTC
Using the GTS, perform Health Check to read current and history DTCs and record them.
Note
CAN communication DTCs are output when there is an open or short in any of the communication lines. Any problems with the power source of a corresponding ECU or sensor, or problems in the ECU, the sensor itself also cause these DTCs to be output.
If a CAN communication line connector is disconnected with the engine switch on (IG), the ECUs of the corresponding system and related systems store a DTC.
Tech Tips
If an open in a CAN main bus line, a short between the CAN bus lines (CANH and CANL) or a +B or ground short in a CAN bus occurs, DTCs of almost all ECUs and sensors on the CAN bus may be output (or a message indicating a communication error may be displayed on the GTS screen). In this case, check the resistance of the CAN bus (steps 7 to 9) first.
If an open occurs in just one of the lines of a CAN branch, 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 on the GTS.
Read the freeze frame data using the GTS and record it.
NEXT |
CHECK COMMUNICATION MALFUNCTION CHECK (CONNECTION STATUS CHECK USING GTS)
Select "Communication Malfunction Check" from the screen on the GTS.
Record all the DTCs stored for ECUs and sensors.
NEXT |
CHECK CAN BUS CHECK (CONNECTION STATUS CHECK USING GTS)
Based on the vehicle equipment and specifications, confirm the systems that use CAN communication Click here.
Select "CAN Bus Check" from the screen on the GTS.
Observe the screen for approximately 2 minutes to check the ECUs and sensors displayed on the screen.
NEXT |
CHECK DLC3 BRANCH LINE AND V BUS MAIN LINE (CANH - CANL)
Note
Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
Tech Tips
Operating the engine switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
Disconnect the cable from the negative (-) battery terminal.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
*a | Front view of DLC3 |
Result | Proceed to |
---|---|
OK | A |
NG (70 Ω or higher) | B |
NG (Below 53 Ω) | C |
B |
Go to "Open in CAN Main Wire" Click here |
C |
Go to "Short in CAN Bus Lines" Click here |
A |
CHECK FOR SHORT TO GND IN V BUS (CANH, CANL - CG)
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
Go to "Short to GND in CAN Bus Line" Click here |
OK |
CHECK FOR SHORT TO +B IN V BUS (CANH, CANL - BAT)
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
Go to "Short to B+ in CAN Bus Line" Click here |
OK |
CHECK RESULT OF CAN BUS CHECK (CONNECTION STATUS CHECK USING GTS)
Inspect or repair the probable malfunctioning part based on the check result of step 6 (the step in which CAN Bus Check was performed).
Result | Proceed to |
---|---|
All ECUs and sensors connected to CAN communication are displayed (CAN bus circuit currently normal) | A |
|
B |
|
C |
|
D |
|
E |
|
F |
|
G |
An ECU (sensor) that is supposed to be connected to the CAN communication system (V bus) is not detected and does not appear on the screen (the branch line of the ECU (sensor) has an open circuit or there is a loss of communication) | H |
|
I |
An ECU (sensor) that is supposed to be connected to the CAN communication system (sub bus 1) is not detected and does not appear on the screen (the branch line of the ECU (sensor) connected to sub bus 1 has an open circuit or there is a loss of communication) Note DTCs indicating a communication malfunction (DTCs that start with U) for the ECUs (sensors) connected to the CAN communication system (sub bus 1) are output by the main body ECU (multiplex network body ECU). Therefore, determine the location of the malfunction using those DTCs. |
I |
An ECU (sensor) that is supposed to be connected to the CAN communication system (sub bus 13) is not detected and does not appear on the screen (the branch line of the ECU (sensor) connected to sub bus 13 has an open circuit or there is a loss of communication) Note DTCs indicating a communication malfunction (DTCs that start with U) for the ECUs (sensors) connected to the CAN communication system (sub bus 2 and sub bus 13) are output by the driving support ECU assembly. Therefore, determine the location of the malfunction using those DTCs. |
I |
An ECU (sensor) that is supposed to be connected to the CAN communication system (sub bus 15) is not detected and does not appear on the screen (the branch line of the ECU (sensor) connected to sub bus 15 has an open circuit or there is a loss of communication) Note DTCs indicating a communication malfunction (DTCs that start with U) for the ECUs (sensors) connected to the CAN communication system (sub bus 15) are output by the certification ECU (smart key ECU assembly). Therefore, determine the location of the malfunction using those DTCs. |
I |
ECUs (sensors) that are supposed to be connected to the CAN communication system do not appear on the screen and other ECUs (sensors) appear and reappear on the screen during confirmation (one of the branch lines of the ECU (sensor) has an open circuit) | J |
Note
Non-installed ECUs or sensors will not be displayed. Do not mistake them for being in communication stop mode.
It may be possible to select buses that do not have ECUs or sensors from the bus selection pull-down menu on the GTS. This is not a malfunction. (This occurs when optional devices are not on a sub bus that is monitored by a gateway function equipped ECU.)
Tech Tips
Regarding CAN Bus Check, refer to How to Interpret CAN Bus Diagnosis (CAN Bus Check) Screen Click here.
If the display of an ECU is intermittent during the check, one side of an ECU or sensor CAN branch wire is open (the signal of the ECU is treated as noise, which affects the response and display of the GTS).
The main body ECU (multiplex network body ECU) checks for proper ECU communication for ECUs that are connected to the sub bus 1 and the results are displayed on the GTS. ECUs that stop communicating with the network gateway ECU for 3 seconds or more will stop being displayed on the GTS.
The driving support ECU assembly checks for proper ECU communication for ECUs that are connected to the sub bus 13 and the results are displayed on the GTS. ECUs that stop communicating with the network gateway ECU for 3 seconds or more will stop being displayed on the GTS.
The certification ECU (smart key ECU assembly) checks for proper ECU communication for ECUs that are connected to the sub bus 15 and the results are displayed on the GTS. ECUs that stop communicating with the network gateway ECU for 3 seconds or more will stop being displayed on the GTS.
w/o Dynamic Rear Steering System:
The network gateway ECU checks for proper ECU communication for ECUs that are connected to the sub bus 2 and the results are displayed on the GTS. ECUs that stop communicating with the network gateway ECU for 3 seconds or more will stop being displayed on the GTS.
For ECUs connected to sub bus 1, sub bus 2, sub bus 13 and sub bus 15 that are in communication stop mode, refer to the flowchart for DTCs related to the communication stop.
w/ Dynamic Rear Steering System:
The network gateway ECU checks for proper ECU communication for ECUs that are connected to the sub bus 18 and the results are displayed on the GTS. ECUs that stop communicating with the network gateway ECU for 3 seconds or more will stop being displayed on the GTS.
The network gateway ECU checks for proper ECU communication for ECUs that are connected to the sub bus 19 and the results are displayed on the GTS. ECUs that stop communicating with the network gateway ECU for 3 seconds or more will stop being displayed on the GTS.
For ECUs connected to sub bus 1, sub bus 13, sub bus 15, sub bus 18 and sub bus 19 that are in communication stop mode, refer to the flowchart for DTCs related to the communication stop.
B |
Go to "DTC U1002" Click here |
C |
Go to "DTC U1002" Click here |
D |
Go to "DTC U1002" Click here |
E |
Go to "DTC U1002" Click here |
F |
Go to "DTC U1103" Click here |
G |
Go to "Gateway ECU Communication Stop Mode" Click here |
H |
Go to "PROBLEM SYMPTOMS TABLE" Click here |
I |
Go to "DIAGNOSTIC TROUBLE CODE CHART" Click here |
J |
Go to "Open in One Side of CAN Branch Line" Click here |
A |
CHECK RESULT OF COMMUNICATION MALFUNCTION CHECK (SELECT THE MALFUNCTIONING BUS)
Inspect or repair the probable malfunctioning part based on the check result of step 5 (the step in which checking for communication malfunction DTCs was performed).
Result | Proceed to |
---|---|
While a DTC indicating a communication malfunction is not being output by a sub bus monitor ECU, the ECUs connected to the V bus have stored DTCs indicating a communication malfunction | A |
|
B |
DTC U1002 (network communication malfunction) is output by the network gateway ECU (the sub bus 19 main line has an open or short circuit) | C |
DTC U1002 (network communication malfunction) is output by the main body ECU (multiplex network body ECU) (the sub bus 1 main line has an open or short circuit) | D |
DTC U1002 (network communication malfunction) is output by the driving support ECU assembly (the sub bus 13 main line has an open or short circuit) | E |
DTC U1103 (network communication malfunction) is output by the certification ECU (smart key ECU assembly) (the sub bus 13 main line has an open or short circuit) | F |
|
G |
Tech Tips
The term ''sub bus monitor ECU'' refers to a gateway function equipped ECU that is able to monitor a bus and store DTCs.
When checking for communication DTCs, refer to How to Interpret Communication DTCs (DTCs that start with U) Click here.
Because a gateway function equipped ECU (sub bus monitor ECU) monitors signals from all ECUs that are connected to its sub bus, a gateway function equipped ECU can detect ECUs with a communication stop more accurately. In this case, perform troubleshooting by referring to the DTC combination table for the sub bus Click here.
If communication DTCs are stored, and all ECUs and sensors connected to the CAN communication system are displayed on the Communication Bus Check (CAN bus check) screen of the GTS, a past malfunction that is currently not occurring is suspected.
Malfunctions in a branch line of the V bus are detected by the corresponding ECUs (sensors). Therefore, determine the location of the malfunction using the combination of output DTCs.
In order to check for malfunctions in sub bus 1, the main body ECU (multiplex network body ECU) checks for a loss of communication and other network communication problems with connected ECUs and stores DTCs when necessary.
In order to check for malfunctions in sub bus 13, the driving support ECU assembly checks for a loss of communication and other network communication problems with connected ECUs and stores DTCs when necessary.
In order to check for malfunctions in sub bus 15, the certification ECU (smart key ECU assembly) checks for a loss of communication and other network communication problems with connected ECUs and stores DTCs when necessary.
w/o Dynamic Rear Steering System:
In order to check for malfunctions in sub bus 2, the network gateway ECU checks for a loss of communication and other network communication problems with connected ECUs and stores DTCs when necessary.
On the GTS, DTCs related to a malfunction in sub bus 2 are displayed under "Gateway CAN".
w/ Dynamic Rear Steering System:
In order to check for malfunctions in sub bus 18 and 19, the network gateway ECU checks for a loss of communication and other network communication problems with connected ECUs and stores DTCs when necessary.
On the GTS, DTCs related to a malfunction in sub bus 18 are displayed under "Multi Bus Monitor 1", and DTCs related to a malfunction in sub bus 19 are displayed under "Multi Bus Monitor 2".
When both the sub bus monitor ECU and the ECUs connected to the V bus store communication DTCs, check and repair the corresponding sub bus first.
B |
Go to "DTC U1002" Click here |
C |
Go to "DTC U1002" Click here |
D |
Go to "DTC U1002" Click here |
E |
Go to "DTC U1002" Click here |
F |
Go to "DTC U1103" Click here |
G |
Go to "DIAGNOSTIC TROUBLE CODE CHART" Click here |
A |
DTC COMBINATION TABLE
Confirm the problem according to the combination of output DTCs regarding the CAN communication system Click here.
Result | Proceed to |
---|---|
Combination of DTCs is not in DTC Combination Table | A |
Combination of DTCs is in DTC Combination Table | B |
Tech Tips
CAN communication system history DTCs may indicate the problem if CAN communication system DTCs are output and all ECUs and sensors connected to the CAN communication system are displayed on "CAN Bus Check" of the GTS.
B |
Go to "COMMUNICATION STOP MODE TABLE" Click here |
A |
IDENTIFICATION OF PROBLEM (PAST MALFUNCTION IN MAIN BUS OF V BUS)
Connect the cable to the negative (-) battery terminal.
Using the GTS, clear all DTCs.
Perform a malfunction simulation test on all harnesses and connectors related to the V bus CAN main wire.
Check the DTCs that were output as a result of the malfunction simulation test. Then determine the malfunctioning area.
Tech Tips
If DTCs are output, do not turn the engine switch off.
NEXT |
REPAIR OR REPLACEMENT
NEXT |
CONFIRMATION TEST
NEXT |
END |