Back Door Closer Switch Malfunction (B2251)
The power back door ECU (power back door motor unit)*1 or back door closer ECU (multiplex network door ECU)*2 receives signals from the latch switch, sector switch and back door courtesy switch, which are built into the back door lock. Based on these switch signals, the latch position of the back door lock is determined.
DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
B2251 |
While the back door closer is operating, a malfunction is detected in position information from the back door courtesy switch within a specified amount of time. |
|
- *1: w/ Power Back Door System
- *2: w/o Power Back Door System
PROCEDURE
READ VALUE USING TECHSTREAM (BACK DOOR COURTESY SWITCH)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Back Door / Data List.
(e) Check if the switch functions properly.
Back Door (Power Back Door ECU*1 or Back Door Closer ECU*2)Tester Display | Measurement Item/Range | Normal Condition | Diagnostic Note |
|---|---|---|---|
Courtesy SW |
Back door courtesy switch signal / ON or OFF |
ON: Back door open OFF: Back door closed |
- |
- *1: w/ Power Back Door System
- *2: w/o Power Back Door System
OK:
The display is as specified in the normal condition column.
Result | Proceed to |
|---|---|
NG |
A |
OK (w/ Power Back Door System) |
B |
OK (w/o Power Back Door System) |
C |
| B | .gif) | REPLACE POWER BACK DOOR ECU (POWER BACK DOOR MOTOR UNIT) |
| C | | REPLACE BACK DOOR CLOSER ECU (MULTIPLEX NETWORK DOOR ECU) |
|
.gif)
INSPECT BACK DOOR LOCK ASSEMBLY (BACK DOOR COURTESY SWITCH)
(a) Remove the back door lock assembly (See page .gif)
).
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Back Door Courtesy SwitchTester Connection | Condition | Specified Condition |
|---|---|---|
3 (CTY) - 4 (E) |
Open-latch |
Below 1 Ω |
3 (CTY) - 4 (E) |
Half-latch |
Below 1 Ω |
3 (CTY) - 4 (E) |
Full-latch |
10 kΩ or higher |
3 (CTY) - 4 (E) |
Over-latch |
10 kΩ or higher |
| NG | | REPLACE BACK DOOR LOCK ASSEMBLY |
|
CHECK HARNESS AND CONNECTOR (BACK DOOR LOCK - POWER BACK DOOR ECU OR BACK DOOR CLOSER ECU)
(a) w/ Power Back Door System
(1) Disconnect the R1 back door lock assembly connector and L20 power back door ECU connector.
(2) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition | Specified Condition |
|---|---|---|
R1-3 (CTY) - L20-20 (FUL) |
Always |
Below 1 Ω |
R1-4 (E) - Body ground |
Always |
Below 1 Ω |
R1-3 (CTY) - Body ground |
Always |
10 kΩ or higher |
*1 |
Front view of wire harness connector (to Back Door Lock) |
*2 |
Front view of wire harness connector (to Power Back Door ECU) |
(b) w/o Power Back Door System (1) Disconnect the R1 back door lock assembly connector and L21 back door closer ECU connector. (2) Measure the resistance according to the value(s) in the table below. Standard Resistance:
|
 |
Result | Proceed to |
|---|---|
NG |
A |
OK (w/ Power Back Door System) |
B |
OK (w/o Power Back Door System) |
C |
| A | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
| B | | REPLACE POWER BACK DOOR ECU (POWER BACK DOOR MOTOR UNIT) |
| C | | REPLACE BACK DOOR CLOSER ECU (MULTIPLEX NETWORK DOOR ECU) |
Test yourself
A quick Toyota Venza quiz: every answer comes with an explanation and a link to the manual page.