Precaution for Trouble Diagnosis
| CAUTION | 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 8
Scheme 9
- 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.
Precautions for Trouble Diagnosis
| CAUTION | 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 10
Scheme 11
- 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.
LAN System: Symptom When Error Occurs in CAN Communication System
In CAN communication system, multiple units mutually transmit and receive signals. Each 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.
LAN System: Self-Diagnosis
| DTC | Self-diagnosis item (SDT indication) | DTC detection condition | Inspection/Action |
|---|---|---|---|
| U0101 | LOST COMM (TCM) | When ECM is not transmitting or receiving CAN communication signal of OBD (emission-related diagnosis) from TCM for 2 seconds or more. | Refer to . |
| U0140 | LOST COMM (BCM) | When ECM is not transmitting or receiving CAN communication signal of OBD (emission-related diagnosis) from BCM for 2 seconds or more. | |
| U1000 | CAN COMM CIRCUIT | 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. | Start the inspection. Refer to the applicable section of the indicated control unit. |
| 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" or "P0607". |
| P0607 | ECM |
DTC DETECTION CONDITION CHART
MONITOR ITEM (ON-BOARD DIAGNOSIS)
Note. For some models, CAN communication diagnosis result is received from the vehicle monitor. (SDT is not available.)
Example: Vehicle Display
| Item | Result indicated | Error counter | Description |
|---|---|---|---|
| CAN_COMM (Initial diagnosis) | OK | 0 | Normal at present |
| NG | 1 - 50 | Control unit error (The number indicates how many times diagnosis has been run.) | |
| CAN_CIRC_1 (Transmission diagnosis) | OK | 0 | Normal at present |
| UNKWN | 1 - 50 | Unable to transmit for 2 seconds or more at present. (The number indicates how many times diagnosis has been run.) | |
| CAN_CIRC_2 - 9 (Reception diagnosis of each unit) | OK | 0 | Normal at present |
| UNKWN | 1 - 50 | Unable to transmit for 2 seconds or more at present. (The number indicates how many times diagnosis has been run.) | |
| Diagnosis not performed. | |||
| No control unit for receiving signals. (No applicable optional parts) |
ITEM DESCRIPTION
Information Needed for Trouble Diagnosis
CAN communication system performs trouble diagnosis with the following tools.
| Tool | Usage |
|---|---|
| Interview sheet | For filling in vehicle information and interview with customer. |
| Data sheet | For copying on-board diagnosis data. |
| Diagnosis sheet | For detecting the root cause. (Diagnosis sheet includes system diagram for every CAN system type) |
| ECU list (On the "Bus check") | For checking the condition of control units and the status of CAN communication. |
| DTC check (SDT) | |
| Bus check (SDT) | |
| CAN communication signal chart | For converting information received from a customer into CAN communication signal transmission and reception. This information can be used to judge whether a circuit between control units is normal or abnormal. |
| Abbreviation list | For checking abbreviations in CAN communication signal chart and diagnosis sheet. |
SPECIAL TOOLS REFERENCE
INSPECTION OF VEHICLE CONDITION
- Check whether or not "U1000" or "U1001" is indicated on "DTC check" by SDT. NOTE: Root cause cannot be detected using the procedure in this section if "U1000" or "U1001" is not indicated.
- 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. The procedures for present errors differ from the procedures for past errors. Refer to " «DETECT THE ROOT CAUSE»(ref-375702-S11695692892010102800000) ".
Create On-board Diagnosis Copy Sheet
Display the trouble diagnosis result of CAN communication with the on-board diagnosis function on the vehicle monitor, etc. Copy them on the on-board diagnosis copy sheet.
Note. For some models, CAN communication diagnosis result is received from the vehicle monitor. (SDT is not available.)
Scheme 12
CREATE DIAGNOSIS SHEET
Note. Be sure to use the diagnosis sheet for the correct CAN system type.
Print Diagnosis Sheet
Print the diagnosis sheet for the applicable CAN system type.
DTC Index
| DTC | Self-diagnosis item (SDT indication) | DTC detection condition | Inspection |
|---|---|---|---|
| U0101 | LOST COMM (TCM) | When ECM is not transmitting or receiving CAN communication signal of OBD (emission-related diagnosis) from TCM for 2 seconds or less. | Refer to How to Use This Section . |
| U0140 | LOST COMM (BCM) | When ECM is not transmitting or receiving CAN communication signal of OBD (emission-related diagnosis) from BCM for 2 seconds or less. | |
| U1000 | CAN COMM CIRCUIT | 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. | Start the inspection. Refer to the applicable section of the indicated control unit. |
| 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" or "P0607". |
| P0607 | ECM |
DTC CHART