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.
2021 Honda Pilot EX, FWDFACTORY OEM SERVICE PROCEDURE
Keyless Access Control Unit
KEYLESS ACCESS CONTROL UNIT DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC | Description | DTC type |
|---|---|---|
| B1601 | Keyless access control unit internal (CPU) error | Internal error |
| B1602 | Keyless access control unit internal (EEPROM) error | Internal error |
| B1632 | MTR CONT signal error | Signal error |
| B1640 | RF1 antenna not connected or malfunction | Signal error |
| B1645 | Driver's door LF antenna circuit short | Signal error |
| B1646 | Driver's door LF antenna circuit open | Signal error |
| B1647 | Passenger's door LF antenna circuit Short | Signal error |
| B1648 | Passenger's door LF antenna circuit open | Signal error |
| B1649 | Driver side rear passenger door LF antenna circuit short | Signal error |
| B1650 | Driver side rear passenger door LF antenna circuit open | Signal error |
| B1651 | Passenger side rear passenger door LF antenna circuit short | Signal error |
| B1652 | Passenger side rear passenger door LF antenna circuit open | Signal error |
| B1659 | Front interior LF antenna circuit short | Signal error |
| B1660 | Front interior LF antenna circuit open | Signal error |
| B1663 | Rear interior LF antenna circuit short | Signal error |
| B1664 | Rear interior LF antenna circuit open | Signal error |
| U1280 | Keyless Access Control Unit communication Bus Line Error (BUS-OFF) | Loss of communication |
| U1281 - Refer to: DTC Troubleshooting: U1281, U128D (Keyless Access Control Unit) (2019 2020 2021) or DTC Troubleshooting: U1281, U128D (Keyless Access Control Unit) (2016 2017 2018) . |
Keyless access control unit lost communication with MICU | Loss of communication |
| U128D - Refer to: DTC Troubleshooting: U1281, U128D (Keyless Access Control Unit) (2016 2017 2018) DTC Troubleshooting: U1281, U128D (Keyless Access Control Unit) (2019 2020 2021) or . |
Keyless access control unit lost communication with gauge control module | Loss of communication |
Factory Service Tools
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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.
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