2001 Sliding door will not lock

Here are the codes you posted along with the possible issues that may have caused each code to be triggered. It's possible the circuit these switches share has a problem that needs to be diagnosed.

It could well be a problem with the wiring or a problem with the connections between the switches and the Multiplex Control Unit, or possibly with the Multiplex Control Unit itself.

B1129

• Driver Side Door Lock Knob Switch Signal Error
• Faulty Driver Side Door Lock Knob Switch
• Driver Side Door Lock Knob Switch harness is open or shorted
• Driver Side Door Lock Knob Switch circuit poor electrical connection
• Faulty Door Multiplex Control Unit

B2077

• Right Power Sliding Door Remote Control Switch 1 Signal Error
• Faulty Right Power Sliding Door Remote Control Switch 1
• Right Power Sliding Door Remote Control Switch 1 harness is open or shorted
• Right Power Sliding Door Remote Control Switch 1 circuit poor electrical connection
• Faulty Right Power Sliding Door Control Unit

B2078

• Right Power Sliding Door Remote Control Switch 2 Signal Error
• Faulty Right Power Sliding Door Remote Control Switch 2
• Right Power Sliding Door Remote Control Switch 2 harness is open or shorted
• Right Power Sliding Door Remote Control Switch 2 circuit poor electrical connection Faulty Right Power Sliding Door Control Unit

B2079

• Right Power Sliding Door Remote Control Switch 3 Signal Error
• Faulty Right Power Sliding Door Remote Control Switch 3
• Right Power Sliding Door Remote Control Switch 3 harness is open or shorted
• Right Power Sliding Door Remote Control Switch 3 circuit poor electrical connection
• Faulty Right Power Sliding Door Control Unit

A child safety lock switch hidden away on the trailing edge of the door can be engaged to prevent opening it, will be a little switch of sort itll move up or down. door will open from outside but not inside for child safety,

take the panel off and have a good look is the only answer i can give here as without a good look i defy anyone to know exactly whats wrong

To start, the noun "''rear latch switch'' is incorrect. It's actually called "Slide Door Lock". It's located on page BO-20 of the Toyota Repair Manual for the 2001 Sienna. There are two door locks on one sliding door. One in the front and one in the rear. Obviously, you want the one in the rear. The location for the "Slide Door Lock" (which also contains an electric switch) is in the rear of the sliding door located mid way up door. You can see (sliding door opened from the back) it without dissembling the door. And, the lock is made up of plastic (dirty white in color).

Sounds like the actuator has frozen up (electric solenoid that moves lock mechanism) You can remove the door panel and spray wd40 into it through the small rubber boot where the linkage enters the solenoid and try to work it up and down, but generally if it's very frozen, it will need to be replaced.

From the back of the front door slide your hand in the sliding door crack and find the child-safety-lever. Push the lever up and/or down while moving the sliding door manual lock/unlock button to the up position. Also works on the non-powered sliding door.

i have replaced many sliding door lock actuators on these vehicles..dealer part..mostly on passenger side sliding door..also possible you have a broken wire in door track harness..follow wiring from door into what looks like a plastic chain in door track at door opening

I had the power sliding side door locks recalled on my 2003 Venture at Dealers expense.