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DTC C1786: Received Limp Home from Transaxle Control Module
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
 
 
OPERATION
ACC-ECU communicates with the TCM via the CAN bus lines.
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITION
This diagnostic trouble code is set when the abnormality below is detected:
  • A signal, which indicates an abnormal transaxle system, is received from the TCM.
 
 
PROBABLE CAUSES
  • Malfunction of the CAN bus line
  • Malfunction of TCM
  • Malfunction of ACC-ECU

 
 
DIAGNOSIS
STEP 1. Diagnose the CAN bus line.
(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. (Refer to GROUP 54C - Explanation About The Scan Tool (M.U.T.-III) Can Bus Diagnostics )
(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 - Diagnosis, Can Bus Diagnostics Table ).
 
STEP 2. Scan tool (M.U.T.-III) other system diagnostic trouble code.
Check the CVT diagnostic trouble code (Refer to GROUP 23A - Diagnosis, Diagnostic Trouble Code Chart ) or the A/T diagnostic trouble code (Refer to GROUP 23C - Diagnosis, Diagnostic Trouble Code Chart ).
Is the diagnostic trouble code set?
Perform the relevant troubleshooting.
Go to Step 3
 
STEP 3. Check the data list.
Using scan tool (M.U.T.-III), check the data list (Refer to data list reference table ).
  • Item 56: transmission fail
Is the check result normal?
Go to Step 4.
Go to Step 4.
 
STEP 4. Check whether the diagnostic trouble code is set again.
Is diagnostic trouble code No.C1786 set?
Replace the ACC-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).