DTC U0101-00 (Adaptive Cruise Control Unit) (2014 2015 2016 2017)

DTC U0101-00  : Lost Communication With the PCM (A/T System)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the how to troubleshooting information .

DTC (ACC)

1. CAN gateway system DTC check

   -1. Turn the vehicle to the ON mode.

   -2. Check for CAN gateway system DTCs with the HDS.

   DTC Description	DTC
   U0029-00 CAN Gateway F-CAN ch A Bus Off
   U0047-00 CAN Gateway F-CAN ch B Bus Off
   U0056-00 CAN Gateway F-CAN ch C Bus Off
   U3000-49 CAN Gateway Internal Failure

   Is DTC U0029-00, U0047-00, U0056-00, and/or U3000-49 indicated?

   YES 

   Go to the indicated DTCs troubleshooting.

   NO 

   Go to step 2.

2. F-CAN circuit communication check

   -1. Select the FUNCTION TEST in the CAN gateway with the HDS, then select the F-CAN Bus Connected Unit Check.

   F-CAN Bus Connected Unit Check

   Which result is indicated?

   PCM (Bus A) is Not Available

   Go to step 3.

   PCM (Bus B) is Not Available

   Go to step 4.

   ACC unit (Bus B) is Not Available

   Go to step 5.

   ACC unit (Bus C) is Not Available

   Go to step 6.

   ACC unit and PCM are Detected

   Intermittent failure, the system is OK at this time.

3. Open wire check (F-CAN A_L, F-CAN A_H lines)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Short the SCS line with the HDS.

   -3. Disconnect the following connectors.

   CAN gateway 24P connector

   PCM connector A (51P)

   -4. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	CAN gateway 24P connector: disconnected
   	PCM connector A (51P): disconnected
   Test circuit	F-CAN A_L
   Test point 1	CAN gateway 24P connector No. 15 (PNK)
   Test point 2	PCM connector A (51P) No. 10 (PNK)

   Test circuit	F-CAN A_H
   Test point 1	CAN gateway 24P connector No. 14 (BLU)
   Test point 2	PCM connector A (51P) No. 9 (BLU)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Check for loose terminals in the CAN gateway 24P connector and PCM connector A (51P). If they are OK, update the PCM if it does not have the latest software , or substitute a known-good PCM , then recheck. If DTC U0101-00 is not indicated after substitution, replace the original PCM .

   NO 

   Repair an open in the wire between the PCM and the CAN gateway.

4. Open wire check (F-CAN B_L, F-CAN B_H lines)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Short the SCS line with the HDS.

   -3. Disconnect the following connectors.

   CAN gateway 24P connector

   PCM connector A (51P)

   -4. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	CAN gateway 24P connector: disconnected
   	PCM connector A (51P): disconnected
   Test circuit	F-CAN B_L
   Test point 1	CAN gateway 24P connector No. 10 (GRY)
   Test point 2	PCM connector A (51P) No. 12 (GRY)

   Test circuit	F-CAN B_H
   Test point 1	CAN gateway 24P connector No. 11 (LT BLU)
   Test point 2	PCM connector A (51P) No. 11 (LT BLU)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Check for loose terminals in the CAN gateway 24P connector and PCM connector A (51P). If they are OK, update the PCM if it does not have the latest software , or substitute a known-good PCM , then recheck. If DTC U0101-00 is not indicated after substitution, replace the original PCM .

   NO 

   Repair an open in the wire between the PCM and the CAN gateway.

5. Open wire check (F-CAN B_L, F-CAN B_H lines)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connectors.

   CAN gateway 24P connector

   ACC unit 20P connector

   -3. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	CAN gateway 24P connector: disconnected
   	ACC unit 20P connector: disconnected
   Test circuit	F-CAN B_L
   Test point 1	CAN gateway 24P connector No. 10 (GRY)
   Test point 2	ACC unit 20P connector No. 13 (GRY)

   Test circuit	F-CAN B_H
   Test point 1	CAN gateway 24P connector No. 11 (LT BLU)
   Test point 2	ACC unit 20P connector No. 2 (LT BLU)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The F-CAN B_L and F-CAN B_H wires are OK. Go to step 7.

   NO 

   Repair an open in the wire between the ACC unit and the CAN gateway.

6. Open wire check (F-CAN C_L, F-CAN C_H lines)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connectors.

   CAN gateway 24P connector

   ACC unit 20P connector

   -3. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	CAN gateway 24P connector: disconnected
   	ACC unit 20P connector: disconnected
   Test circuit	F-CAN C_L
   Test point 1	CAN gateway 24P connector No. 8 (PNK)
   Test point 2	ACC unit 20P connector No. 15 (PNK)

   Test circuit	F-CAN C_H
   Test point 1	CAN gateway 24P connector No. 9 (PUR)
   Test point 2	ACC unit 20P connector No. 4 (PUR)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The F-CAN C_L and F-CAN C_H wires are OK. Go to step 7.

   NO 

   Repair an open in the wire between the ACC unit and the CAN gateway.

7. ACC unit check (update)

   -1. Reconnect the following connectors.

   CAN gateway 24P connector

   ACC unit 20P connector

   -2. Update the ACC unit if it does not have the latest software .

   -3. Turn the vehicle to the OFF (LOCK) mode.

   -4. Turn the vehicle to the ON mode, then wait for at least 5 seconds.

   -5. Check for DTCs with the HDS.

   DTC Description	DTC	Freeze Frame

   Is DTC U0101-00 indicated?

   YES 

   Check for loose terminals in the ACC unit 20P connector. If the ACC unit was updated and the symptom/indication is still present, replace the ACC unit .

   NO 

   Troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTC's troubleshooting.