[john.desaavedra]

Recently, both fobs stopped working. Both batteries are good. After examining the remote receiver, it was found to have an open circuit between the power leads. It was receiving 12 volts from the ECU. I replaced the receiver with a salvaged unit. Before installing, I tested the unit and found it has reasonable resistance between the power leads. I have attempted many times to enter programming mode to register the fobs with the replacement receiver but to no avail. All door locks operate flawlessly, and all fuses are good. I initially had some low voltage codes from a recent battery failure so those have been cleared. I have discharged the system by disconnecting the battery cables and turning on the headlights. I have replaced a receiver and reprogrammed on another Toyota and it took a single attempt. Note: when using a scan tool (X-Tool D-7) I can access the menu to program fobs, but instead of working it gives a failure to communicate message. Also the other bi-directional body functions, aside from the driver's window, do not work. Any suggestions? Is there a possibility of a fault with the ECU?

 

[carguy75]

I would suggest that you connect the Highlander to a battery charger while you try to use the scan tool. Sometimes the battery may not be properly charged(under 12volts) which causes glitches in the ECU and modules. A battery charger will keep the system properly powered while using the scan tool.

 

[john.desaavedra]

Checked battery voltage as well. 12.5+ volts. Thanks for the response. I'm pretty persistent so I'm not giving up easily. Also noted these are the original keys and fobs. No fobs have been added. I will try a battery charger but not expecting that will make any difference. I can go through the steps quickly on my 2003 Camry and get into programming mode in 20 seconds.

 

[carguy75]

No problem.

Good luck; hopefully you get it to work.

Note: The issue could be that the salvage remote receiver is a dud even though it tested out fine resistance wise due to some other internal fault.

 

[john.desaavedra]

Resolution: After failing repeatedly to program the replacement unit, I contacted the seller to ask if the unit had been tested. A second resistance test indicated the power circuit was open on the replacement unit. The initial test indicated 2.4 ohms, which I now know to be too low. With this information, the seller quickly refunded the purchase price and advised me to toss the unit. I ordered a second used unit; this time from a seller who advertises the unit to be tested and guaranteed. I tested the power side resistance which was at 12.7 ohms. I installed the unit and at first the system did not go into programming mode. I attempted to program with a scan tool and it failed to communicate. I slowly cycled the key, attempted to manually enter programming mode, and after about 10 seconds, the locks cycled, indicating the ECU had entered programming mode. I programmed in my two fobs and all is well. Thank you Carguy75 for stepping up to assist. It was indeed a faulty receiver from the first vendor. Lesson here is until there is a functioning receiver that has been recognized by the ECU, the system will not enter programming mode, leaving the fault difficult to diagnose.

 

[john.desaavedra]

After a week of working as designed, the replacement keyless entry receiver module failed again. Dang!

 

[john.desaavedra]

Does anyone know what can cause the failure? Is there a control module that can kill the receiver?

 

[john.desaavedra]

I found another junk yard receiver and it went into programming mode without delay. We shall see. It seems nobody know much about this system. Apparently the Ohm meter testing is not conclusive. The most recent unit tested at 2.4 and it worked fine. There was a 4-Runner next to the Highlander in the junk yard and it's receiver also tested at 2.4 ohms across the power leads.