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DTC C1803 ACC mode off disagreement
DTC C1804 ACC deactivation disagreement
 
 
cautionBefore replacing the ECU, ensure that the communication circuit is normal.
 
 
OPERATION
The ASC-ECU receives ACC control status signal from the ACC-ECU, and vehicle control status signal from the ECM via CAN bus lines, respectively.
 
 
 
DTC SET CONDITIONS
If the information received from the ACC-ECU does not correspond to that received from the ECM, the ASC-ECU will set the DTC.
 
 
 
TROUBLESHOOTING HINTS
  • Wiring harness or connector failure of CAN bus line
  • Malfunction of ECM
  • Malfunction of ACC-ECU
  • Malfunction of ASC-ECU
 
 
 
 
DIAGNOSIS
STEP 1. Scan tool (M.U.T.-III) CAN bus diagnostics
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 3.
 
STEP 2. Scan tool (M.U.T.-III) DTC of other system
Use scan tool (M.U.T.-III) to check that the DTC is set in the engine control module and ACC-ECU.
Is the DTC set?
Troubleshoot for the relevant DTC. Refer to GROUP 13A - Troubleshooting <ECM (2.4L ENGINE)>, GROUP 13B - Troubleshooting <ECM (3.0L ENGINE)>, or GROUP 17 - Adaptive Cruise Control System (ACC) <ACC-ECU>.
Go to Step 3.
 
STEP 3. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Ignition switch "LOCK" (OFF)
(3) Ignition switch "ON"
Is DTC No.C1803 or C1804 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 4.
This diagnosis is complete.
 
STEP 4. Check whether the DTC is set again.
(1) Erase the DTC.
(2) Ignition switch "LOCK" (OFF)
(3) Ignition switch "ON"
Is DTC No.C1803 or C1804 set?
Return to Step 1.
This diagnosis is complete.