C1616

C1616

Component Location:

General Description
The HECU send requirement data, such as Torque reduction, the number of fuel cut cylinders, and TCS control requests, to the Engine ECU & TCU through CAN bus line.
The Engine ECU performs fuel cut functions according to requests from the HECU and retards ignition timing by torque reduction requests.
The TCU 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 ESC control, and sets this code if re-initialization is tried for 15 times in sequence without success.

DTC Detecting Condition:

Schematic Diagram:

Signal Waveform:

Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness (es) and terminals. 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 "Signal Circuit Inspection" procedure.

Signal Circuit Inspection
1. Ignition "OFF".
2. Disconnect the HECU harness connector.
3. Measure resistance between terminal "14" of the HECU harness connector and terminal "35" of the HECU harness connector.

Specification : Approx. 60 ohms






4. Is the measured resistance within specifications?

YES - Fault is intermittent caused by open or short in CAN signal harness or was repaired and HECU memory was not cleared, go to "CAN Bus Short (to ground) Inspection" procedure.

NO - Check for open or short in CAN signal harness between terminal "14" of the HECU harness connector and terminal "35" of the HECU harness connector. Repair as necessary and then go to "Verification of vehicle Repair" procedure.

CAN Bus Short (to ground) Inspection
5. Ignition "OFF".
6. Disconnect the HECU harness connector.
7. Measure resistance between terminal "14,35" of the HECU harness connector and chassis ground.

Specification : Approx. Infinity ohms






8. Is the measured resistance within specifications?

YES - Go to "CAN Bus Short (between HIGH and LOW) Inspection" procedure.

NO
a. Check for short to ground in CAN HIGH signal harness in case of abnormal resistance measured between terminal "35" of the HECU harness connector and chassis ground. Repair as necessary and then go to "Verification of vehicle Repair" procedure.
b. Check for short to ground in CAN LOW signal harness in case of abnormal resistance measured between terminal "14" of the HECU harness connector and chassis ground. Repair as necessary and then go to "Verification of vehicle Repair" procedure.

CAN Bus Short (between HIGH and LOW) Inspection
9. Ignition "OFF".
10. Disconnect all the connector related to CAN such as HECU, PCU, EPS, ECS harness connector.
11. Measure resistance between terminal "14,35" of the HECU harness.

Specification : Approx. 120 ohms






12. Is the measured resistance within specifications?

YES - Go to "Verification of vehicle Repair" procedure.

NO - Check for short in CAN signal harness between terminal "14" of the HECU harness connector and terminal "35" of the HECU harness connector.
Repair as necessary and then 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 scantool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Using a scantool, Clear DTC.
3. Operate the vehicle within DTC Detecting Condition in General Information.
4. Are any DTCs present?

YES - Go to the applicable troubleshooting procedure.

NO - System performing to specification at this time.