Precautions for Trouble Diagnosis
| CAUTION | Follow the instructions listed below. Failure to do this may cause damage to parts: Never apply 7.0 V or more to the measurement terminal. Use a tester with open terminal voltage of 7.0 V or less. Turn the ignition switch OFF and disconnect the battery cable from the negative terminal when checking the harness. |
Scheme 5
Scheme 6
- Solder the repaired area and wrap tape around the soldered area. NOTE: A fray of twisted lines must be within 110 mm (4.33 in).
- Bypass connection is never allowed at the repaired area. NOTE: Bypass connection may cause CAN communication error. The spliced wire becomes separated and the characteristics of twisted line are lost.
- Replace the applicable harness as an assembly if error is detected on the shield lines of CAN communication line.
WHEN DTC OF CAN COMMUNICATION IS INDICATED EVEN THOUGH CAN COMMUNICATION SYSTEM IS NORMAL
- Removal/installation of parts: Error may be detected when removing and installing CAN communication unit and related parts while turning the ignition switch ON. (A DTC except for CAN communication may be detected.)
- Fuse blown out (removed): CAN communication of the unit may cease.
- Voltage drop: Error may be detected if voltage drops due to discharged battery when turning the ignition switch ON (Depending on the control unit which carries out CAN communication).
- Error may be detected if the power supply circuit of the control unit, which carries out CAN communication, malfunctions (Depending on the control unit which carries out CAN communication).
- Error may be detected if reprogramming is not completed normally.
Note. CAN communication system is normal if DTC of CAN communication is indicated on SELF-DIAG RESULTS of CONSULT under the above conditions. Erase the memory of the self-diagnosis of each control unit.
Symptom When Error Occurs in CAN Communication System
In CAN communication system, multiple control units mutually transmit and receive signals. Each control unit cannot transmit and receive signals if any error occurs on CAN communication line. Under this condition, multiple control units related to the root cause malfunction or go into fail-safe mode.
CAN Diagnosis with CONSULT
CAN diagnosis on CONSULT extracts the root cause by receiving the following information.
- Response to the system call
- Control unit diagnosis information
- Self-diagnosis
- CAN diagnostic support monitor
Self-Diagnosis
If communication signals cannot be transmitted or received among control units communicating via CAN communication line, CAN communication-related DTC is displayed on the CONSULT "Self Diagnostic Result" screen.
Note. The following table shows examples of CAN communication-related DTC. For other DTC, refer to the applicable sections.
| DTC | Self-diagnosis item (CONSULT indication) | DTC detection condition | Inspection/Action | |
|---|---|---|---|---|
| U1000 | CAN COMM CIRCUIT | ECM | When ECM is not transmitting or receiving CAN communication signal of OBD (emission-related diagnosis) for 2 seconds or more. | Start the inspection. Refer to the applicable section of the indicated control unit. |
| Except for ECM | When a control unit (except for ECM) is not transmitting or receiving CAN communication signal for 2 seconds or more. | |||
| U1001 | CAN COMM CIRCUIT | When ECM is not transmitting or receiving CAN communication signal other than OBD (emission-related diagnosis) for 2 seconds or more. | ||
| U1002 | SYSTEM COMM | When a control unit is not transmitting or receiving CAN communication signal for 2 seconds or less. | ||
| U1010 | CONTROL UNIT (CAN) | When an error is detected during the initial diagnosis for CAN controller of each control unit. | Replace the control unit indicating "U1010". | |
Scheme 7
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.