DTC B1829

WARNING: This page is about a different car, the 2022 Honda Accord, 2021 Honda Accord, 2020 Honda Accord, 2019 Honda Accord, and 2018 Honda Accord. However, it is still accessible from the selected car via links, so may be relevant.

DTC B1829 : AT-P Signal and VSP Signal Mismatch

NOTE:

If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .
If you have any loss of communication DTCs for the power seat control unit, troubleshoot those DTCs first.
If the shift position indicator comes on, check the A/T system troubleshooting.

DTC Description	DTC
B1829 AT-P signal and VSP signal mismatch

DTC (Power Seat Control Unit)

Problem verification

-1. Clear the DTCs with the HDS.

-2. Start the engine.

-3. Test drive at 6 mph (10 km/h) for 10 seconds.

-4. Check for DTCs with the HDS.

DTC Description	DTC
B1829 AT-P signal and VSP signal mismatch

Is DTC B1829 indicated?

YES: A/T

Go to step 2.

YES: CVT

Go to step 3.

Intermittent failure, the system is OK at this time. Check for loose or poor connections.

Open wire check (ATP-PBK/ATP-P line)

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

-2. Disconnect the following connectors.

Power seat control unit connector A (20P)
TCM connector A (23P)

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

Test condition	Vehicle OFF (LOCK) mode Power seat control unit connector A (20P): disconnected TCM connector A (23P): disconnected
Test point 1	Power seat control unit connector A (20P) No. 1
Test point 2	TCM connector A (23P) No. 22

Is there continuity?

YES

Go to step 4.

Repair an open or high resistance in the wire between the power seat control unit and the TCM.

Open wire check (ATP-PBK/ATP-P line)

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

-2. Disconnect the following connectors.

Power seat control unit connector A (20P)
Transmission range switch 10P connector

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

Test condition	Vehicle OFF (LOCK) mode Power seat control unit connector A (20P): disconnected Transmission range switch 10P connector: disconnected
Test point 1	Power seat control unit connector A (20P) No. 1
Test point 2	Transmission range switch 10P connector (female terminals) No. 5:

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

Is there continuity?

YES

Go to step 4.

Repair an open or high resistance in the wire between the power seat control unit and the transmission range switch.

Shorted wire check (ATP-PBK/ATP-P line)

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

Test condition	Vehicle OFF (LOCK) mode Power seat control unit connector A (20P): disconnected TCM connector A (23P) (A/T): disconnected Transmission range switch 10P connector (CVT): disconnected
Test point 1	Power seat control unit connector A (20P) No. 1
Test point 2	Body ground

Is there continuity?

YES

Repair a short to ground in the wire between the power seat control unit and the TCM (A/T)/Transmission range switch (CVT).

Replace the power seat control unit .