C1616
DTC C1616 CAN BUS OFFCOMPONENT LOCATION:
GENERAL DESCRIPTION
The HECU send requirement data, such as Torque reduction, the number of fuel cut cylinders, and ESC control requests, to the Engine PCM (ECM TCM) through CAN bus line.
The Engine PCM (ECM) performs fuel cut functions according to requests from the HECU and retards ignition timing by torque reduction requests.
The PCM (TCM) maintains current gear positions during ESC control time, in order not to increase power which causes a Kickdown shift.
DTC DESCRIPTION
The HECU checks the CAN communication lines for normal TCS control, and sets this code if CAN BUS OFF status is detected for more than 100ms.
DTC DETECTING CONDITION:
SCHEMATIC DIAGRAM:
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness (es) and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
NO
Go to "CAN Signal Circuit Inspection" procedure.
CAN SIGNAL CIRCUIT INSPECTION
SHORT CHECK (TO GROUND)
1. Ignition "OFF" Engine "OFF".
2. Disconnect the HECU connector.
3. Measure resistance between CAN LOW terminal, CAN HIGH terminal of the HECU harness connector and chassis ground.
Specification: infinite ohms
4. Is the measured value within specifications?
YES
Go to next procedure.
NO
If abnormal resistance is detected in CAN HIGH circuit, Repair short to ground in CAN HIGH circuit and then go to "Verification of Vehicle Repair" procedure.
If abnormal resistance is detected in CAN LOW circuit, Repair short to ground in CAN LOW circuit and then go to "Verification of Vehicle Repair" procedure,
CAN BUS RESISTANCE CHECK
1. Ignition "OFF" Engine "OFF".
2. Disconnect the HECU connector.
3. Measure resistance between CAN LOW terminal and CAN HIGH terminal of the HECU harness connector.
Specification: Approximately 60 ohms
4. Is the measured value within specifications?
YES
Go to "Component Inspection" procedure.
NO
In case of the resistance "approximately 19 Repair mutual short in CAN signal circuit of the HECU. and then go to "Verification of Vehicle Repair" procedure.
In case of the resistance ohms Repair open in CAN signal circuit of the HECU and then go to "Verification of Vehicle Repair" procedure.
In case of the resistance "approximately 120 ohms Check the resistances (122 ohms in I/P junction box and ECM, repair as necessary and then go to "Verification of Vehicle Repair" procedure.
COMPONENT CIRCUIT INSPECTION
1. Ignition "OFF".
2. Ignition "ON" Engine "OFF".
3. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
4. Using a scan tool, Clear DTC.
5. Select "Diagnostic Trouble Codes (DTCs)" mode again.
6. Are any DTCs present
YES
Substitute with a known-good HECU and check for proper operation.
If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.
NO
Fault is intermittent caused by poor connection in CAN signal harness and/or HECU's connector. Go to "Verification of Vehicle Repair" procedure.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Using a scan tool, Clear DTC.
3. Operate the vehicle within DTC Detecting Condition in General Information.
4. Using a scan tool, Check DTC present.
5. Are any DTCs present
YES
Go to the applicable troubleshooting procedure.
NO
System performing to specification at this time.