Part 2

NETWORKING: CAN COMMUNICATION SYSTEM: DIAGNOSIS SYSTEM (Continued..)

8. DTC COMBINATION TABLE (OPEN IN CAN BRANCH OF SUB BUS, PAST COMMUNICATION ERROR)

(a) Regarding a past communication error of ECUs and sensors connected to sub bus 11 (in this case, normal was displayed when performing the CAN Bus Check, but communication DTCs are output), determine the part that had a malfunction based on DTCs output from the network gateway ECU.

HINT
* As gateway function equipped ECUs (sub bus monitor ECU) monitor signals from all ECUs that are connected to sub buses, gateway function equipped ECUs can detect ECUs with a communication stop more accurately.
* DTCs output from ECUs other than the power management control ECU (gateway function equipped ECU) are shown only as a reference
* Regarding a communication stop that is currently occurring in sub bus 11, the malfunctioning part can be confirmed easily by performing the CAN bus check using the Techstream.
* 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.

HINT
* o: Set
* X: Not set or may be set according to the malfunctioning part when one line of a CAN branch is open.
* -: DTC is not output.
* *1: DTC is not output during communication error, but will be output as a history DTC (past DTC) when communication returns to normal.
* *2: Communication of all the ECUs or sensors connected to sub bus 11 stops.
* *3: Gateway function equipped ECUs relay signals between the ECUs connected to the different buses.
* 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.

9. DTC COMBINATION TABLE (OPEN IN CAN BRANCH OF SUB BUS, PAST COMMUNICATION ERROR)

(a) Regarding a past communication error of ECUs and sensors connected to sub bus 12 (in this case, normal was displayed when performing the CAN Bus Check, but communication DTCs are output), determine the part that had a malfunction based on DTCs output from the network gateway ECU.

HINT
* As gateway function equipped ECUs (sub bus monitor ECU) monitor signals from all ECUs that are connected to sub buses, gateway function equipped ECUs can detect ECUs with a communication stop more accurately.
* DTCs output from ECUs other than the power management control ECU (gateway function equipped ECU) are shown only as a reference.
* Regarding a communication stop that is currently occurring in sub bus 12, the malfunctioning part can be confirmed easily by performing CAN Bus Check using the Techstream.
* 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.

HINT
* This waveform is measured between terminals CANH and GND, and terminals CANL and GND of the DLC3. (Use this as a reference for diagnosis of CAN communication lines.)
* When malfunctions in multiple ECUs are suspected based on CAN Bus Check and DTCs checked using the Techstream, check the resistance of the CAN bus using an ohmmeter first How to Proceed With Troubleshooting. If no problems are found, check the following waveforms.
* If a waveform is not similar to one of the following 3 patterns (Group 1), then an open in a CAN main bus line, an open in a CAN branch line, or a short between a CAN line (CANH or CANL) and ground is suspected (Group 2).
* Wiggle the connector and wire harness to check if the waveform changes.

(a) CAN bus waveforms (Group 1)

(1) Normal waveform

(2) Open in both of the lines (CANH and CANL) of a CAN branch

HINT
* Waveforms (waveforms shown using dotted lines) are not present from an ECU or sensor connected to a CAN branch with an open circuit in both lines. (Waveforms from other ECUs or sensors are normal.)
* Because this waveform is similar to a normal waveform, instead of using the waveform, the malfunctioning part can be narrowed down by performing a CAN bus check.

(3) Short between the CAN bus lines (CANH and CANL)

HINT
* Waveforms disappear.
* If the malfunction is in an ECU, disconnecting the ECU will change the waveform. If the waveform does not change, a malfunction in the wire harness is suspected.

(b) CAN bus waveforms (reference) (Group 2)

NOTICE:
The following CAN bus waveforms can be used only as reference. The actual measured waveform may differ significantly depending on the location of the open or short circuit.

(1) Open in a CAN branch line (CANH)

HINT
* An abnormal waveform is output from an ECU with an open in one of its CAN branch lines. Because this abnormal output interferes with the signals from other ECUs, the output of other ECUs will also appear abnormal.
* Narrow down the malfunctioning part by checking DTCs or performing a CAN bus check, or by checking waveform changes when ECUs or sensors are disconnected. The waveform will change to one for an open in both sides of a CAN branch when the ECU or sensor with an open CAN branch line is disconnected.

(2) Open in a CAN branch line (CANL)

HINT
* Waveforms of ECUs or sensors that are nearer to the DLC3 than the open part are almost normal.
* Waveforms of ECUs or sensors that are on the opposite side of the DLC3 from the open part are abnormal.
* An open in a CAN main bus line can be confirmed by measuring the resistance between the CANH and CANL terminals of any CAN branch.

(4) Short between a CAN bus line (CANH) and ground

HINT
* Narrow down the shorted part by checking for waveform changes when disconnecting connectors from the CAN junction connector or when disconnecting ECUs or sensors.
* A short to ground in the CANL line can be confirmed by measuring the resistance between CANL and ground using an ohmmeter.

11. DATA SENDING/RECEIVING TABLE

(a) Data sending/receiving table

HINT
If Data List items related to sent/received data are not displayed properly, the part for which communication is interrupted can be determined using the table below.

*1: Whether the ECU that sends data is functioning or not can be judged by using the Techstream to check items such as switches or sensors that send signals to the ECU via direct lines.

*2: Although the received contents cannot be checked in the Data List, whether or not the data is received normally can be checked by observing the combination meter.

*3: The combination meter assembly receives a vehicle speed signal from the brake actuator assembly (skid control ECU) and sends the signal to other ECUs.

(b) Details of relevant Data List items (Selected system: Hybrid Control )

NOTICE:
* Some Data List values may vary significantly if there are slight differences in the environment in which the vehicle is operating when measurements are obtained. Variations may also occur due to aging of the vehicle. Due to these considerations, it is not always possible to provide definite values to be used for judgment of malfunctions. It is possible that a malfunction may be present even if measured values are within the reference range.
* In the event of a problem with intricate symptoms, collect sample data from another vehicle of the same model operating under identical conditions in order to reach an overall judgment by comparing all the items in the Data List.

(1) Connect the Techstream to the DLC3.

(2) Turn the power switch on (IG).

(3) Enter the following menus: Powertrain / Hybrid Control / Data List.

(4) Check the results by referring to the following table.

Hybrid Control

HINT
When reviewing Data List information, try to select only the specific Data List items related to the inspection being performed. If all items are selected when checking the Data List, the interval between updates for each item will be longer, resulting in delayed or incorrect data.

(c) Details of relevant Data List items (Selected system: Engine and ECT)

HINT
Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

NOTICE:
In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

(1) Warm up the engine.

(2) Turn the A/C switch off.

(3) Turn the power switch off.

(4) Connect the Techstream to the DLC3.

(5) Turn the power switch on (IG).

(6) Turn the Techstream on.

(7) Enter the following menus: Powertrain / Engine and ECT / Data List.

(8) According to the display on the Techstream, read the Data List.

Engine and ECT

(d) Details of relevant Data List items (Selected system: Air Conditioner)

HINT
Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

NOTICE:
In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

(1) Turn the power switch off.

(2) Connect the Techstream to the DLC3.

(3) Turn the power switch on (IG).

(4) Turn the Techstream on.

(5) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(6) Check the value(s) by referring to the table below.

Air Conditioner

(e) Details of relevant Data List items (Selected system: Combination Meter)

HINT
Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

NOTICE:
In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

(1) Warm up the engine.

(2) Turn the power switch off.

(3) Connect the Techstream to the DLC3.

(4) Turn the power switch on (IG).

(5) Turn the Techstream on.

(6) Enter the following menus: Body Electrical / Combination Meter / Data List.

(7) Check the values by referring to the table below.

Combination Meter

(f) Details of relevant Data List items (Selected system: Power Source Control)

HINT
Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

NOTICE:
In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

(1) Connect the Techstream to the DLC3.

(2) Turn the power switch on (IG).

(3) Turn the Techstream on.

(4) Enter the following menus: Body Electrical / Power Source Control / Trouble Codes.

(5) Read the Data List according to the display on the Techstream.

Power Source Control

(g) Details of relevant Data List items (Selected system: ABS/VSC/TRAC)

HINT
Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

NOTICE:
In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

(1) Warm up the engine.

(2) Turn the power switch off.

(3) Connect the Techstream to the DLC3.

(4) Turn the power switch on (IG).

(5) Turn the Techstream on.

(6) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

(7) According to the display on the Techstream, read the Data List.