DTC U0101-00 (2014 2015 SRS Unit)

DTC U0101-00  : Lost Communication With the PCM (PGM-FI system)

NOTE: Before doing this troubleshooting procedure, find out if the vehicle was in a collision. If so, verify that all the required components were replaced with new components of the correct part number, and that they were properly installed .
• Before doing this troubleshooting procedure, review SRS Precautions and Procedures , General Troubleshooting Information , and Battery Terminal Disconnection and Reconnection - Refer to: Battery Terminal Disconnection and Reconnection (2014 2015) .
• Before replacing the SRS unit, check the SRS unit software version with the HDS. If the software version is not the latest, update the SRS unit software , and retest.

DTC (SRS)

1. Body electrical system check

   -1. Check for any F-CAN and B-CAN communication DTCs with the HDS.

   DTC Description	DTC

   Are there any communication DTCs?

   YES 

   Go to the appropriate DTC troubleshooting.

   NO 

   Go to step 2.

2. DTC check

   -1. Clear the DTCs with the HDS.

   - 2. Turn the vehicle to the ON mode, then wait for 10 seconds.

   - 3. Check for DTCs with the HDS.

   DTC Description	DTC
   U0101-00 Lost communication with the PCM (PGM-FI system)

   Is DTC U0101-00 indicated?

   YES 

   Go to step 3.

   NO 

   Intermittent failure, the system is OK at this time. Go to Troubleshooting Intermittent Failures . If another DTC is indicated, troubleshoot the DTC.

3. PGM-FI system check

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

   - 2. Start the engine, and see if the malfunction indicator lamp (MIL) also stays on.

   Does the MIL stay on longer than 30 seconds?

   YES 

   Go to the Fuel and Emissions Systems General Troubleshooting Information - Refer to: How to Troubleshoot the A/T System (2014 2015), .

   NO 

   Go to step 4.

4. Open wire check (F-CAN_H, F-CAN_L lines)

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

   - 2. Disconnect the following connector.

   Disconnect PCM connector A (51P) - Refer to: How to Troubleshoot the A/T System (2014 2015), or How to Troubleshoot the Fuel and Emissions Systems,

   - 3. Disconnect the negative cable from the battery, then wait at least 3 minutes.

   - 4. Disconnect the following connector.

   SRS unit connector A (39P) - Refer to: SRS Unit Removal and Installation,

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

   Test condition	Vehicle OFF (LOCK) mode
   	PCM connector A (51P): disconnected
   	SRS unit connector A (39P): disconnected
   Test circuit	F-CAN_H
   Test point 1	SRS unit connector A (39P) No. 20
   Test point 2	PCM connector A (51P) No. 9 (WHT)

   Test circuit	F-CAN_L
   Test point 1	SRS unit connector A (39P) No. 21
   Test point 2	PCM connector A (51P) No. 10 (BLK)

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

   Is there continuity?

   YES 

   The F-CAN_H and F-CAN_L wires are OK. Faulty SRS unit or poor connection at SRS unit connector A (39P) and the SRS unit. Check the connection; if the connection is OK, replace the SRS unit - Refer to: SRS Unit Removal and Installation, or SRS Unit Removal and Installation (2017 2018 2019 2020) . If the DTC does not clear, replace the engine compartment wire harness or the dashboard wire harness.

   NO 

   Open in the harness between SRS unit connector A (39P) terminal No. 20 and PCM connector A (51P) terminal No. 9, or between SRS unit connector A (39P) terminal No. 21 and PCM connector A (51P) terminal No. 10 (floor wire harness or dashboard wire harness); replace the faulty harness, then clear the DTC.