Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC U1281 (2017 2018 2019 2020)
DTC U1281 : Keyless Access Control Unit lost communication with MICU
| DTC Description | DTC |
|---|---|
| U1281 Keyless Access Control Unit lost communication with MICU |
DTC (Keyless Access Control Unit)
If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2017 2018 2019 2020) .
- Problem verification
-1. Clear the DTCs with the HDS.
- 2. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.
- 3. Wait for at least 6 seconds.
- 4. Check for DTCs with the HDS.
DTC Description DTC U1281 Keyless Access Control Unit lost communication with MICU Is DTC U1281 indicated?
YES
Go to step 2.
NO
Intermittent failure, the system is OK at this time. Check for loose or poor connections.
- Open wire check (B-CAN lines)
-1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Disconnect the receiving control unit connector.
Keyless access/TPMS control unit connector C (20P) - 3. Disconnect the transmitting control unit connectors.
Driver's under-dash fuse/relay box connector H (13P) - 4. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) modeKeyless access/TPMS control unit connector C (20P): disconnectedDriver's under-dash fuse/relay box connector H (13P): disconnected Test point 1 Keyless access/TPMS control unit connector C (20P) (female terminals) No. 1: Test point 2 Driver's under-dash fuse/relay box connector H (13P) No. 5 - Refer to: MICU Input Test (2017 2018 2019 2020) Test point 1 Keyless access/TPMS control unit connector C (20P) (female terminals) No. 11: Test point 2 Driver's under-dash fuse/relay box connector H (13P) No. 10 - Refer to: MICU Input Test (2017 2018 2019 2020) Is there continuity?
YES
The B-CAN_L to B-CAN_H wire is OK. Go to step 3.
NO
Repair an open or high resistance in the wire(s).
- Determine possible failure area (the receiving control unit or the transmitting control unit)
-1. Reconnect all connectors.
- 2. Clear the DTCs with the HDS.
- 3. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.
- 4. Wait for at least 6 seconds.
- 5. Check for DTCs with the HDS.
DTC Description DTC U1281 Keyless Access Control Unit lost communication with MICU Is DTC U1281 indicated?
YES
Check for loose terminals and poor connections in the receiving control unit connector. Check is OK, replace the keyless access/TPMS control unit .
NO
The receiving control unit is OK at this time. Replace the MICU - Refer to: Driver's Under-Dash Fuse/Relay Box Removal and Installation, or Passenger's Under-Dash Fuse/Relay Box Removal and Installation .
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.