C1612

C1612

Component Location:

General Description
The HECU sends requirement data, such as Torque reduction, the number of fuel cut cylinders, and TCS 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 TCS 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 an TCM message is not received within 500 ms. The HECU does not detect this code until 3 seconds after the IG KEY is turned to ON.

DTC Detecting Condition:

Schematic Diagram:

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
a. Repair as necessary and then go to "Verification of Vehicle Repair" procedure.

NO
a. Go to "Component Inspection" procedure.

Component Inspection
1. Ignition "OFF".
2. Ignition "ON".
3. Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode
4. Using a scantool, Clear DTC.
5. Select "Diagnostic Trouble Codes (DTCs)" mode again.
6. Are any DTCs present?

YES
a. Substitute with a known-good PCM (TCM) and check for proper operation. If problem is corrected, replace PCM (TCM) and then go to "Verification of Vehicle Repair" procedure. If NG, replace HECU and then go to "Verification of Vehicle Repair" procedure.

NO
a. Fault is intermittent caused by faulty HECU or was repaired and HECU memory was not cleared. 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
a. Go to the applicable troubleshooting procedure.

NO
a. System performing to specification at this time.