C1604

C1604

Component Location:

General Description
The HECU is composed of a ECU (Electronic Control Unit) and a HCU (Hydraulic Control Unit), so the HECU hardware includes all solenoid valves inside the unit as well as the ECU.

DTC Description
The HECU monitors the operation of the IC components such as memory, register, A/D converter and so on.
The HECU sets this code when the EEPROM data read by the master processor is different than prior data writen, or when the master/slave processor detects abnormal operation in RAM, Status Register, Interrupt, Timer, A/D converter or cycle time.

DTC Detecting Condition:

Component Inspection
1. Ignition "OFF".
2. Engine "ON".
3. Does warning lamp remain On?

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 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 scan tool 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.