This weekend I was replacing my radiator, thermostat, and hoses and to my surprise I saw the secondary air intake sensor hanging freely zip tied behind the radiator. Then I checked around and all of the SAI hardware is still in place. I'm not sure who or what shop replaced the radiator last and just omitted connecting the sensor.

The new radiator has a plug for the sensor so I could connect it, but I'm wondering how I can test to see if the SAI system has an error or is functioning properly prior to the previous owner/mech disconnecting the sensor. I'm wondering what kind of problems this could be causing, etc. I have no codes when I scan so I'm curious that with the sensor unplugged but no delete for the rest of the system, what's going on.

I searched around but didn't see much about these mods or deletes.

Any thoughts? How to test or what to look at before connecting the sensor and seeing what breaks?

 

Unless you have a replacement ECU it should be throwing a code if the SAI is not functioning.

You probably know that SAI is an unnecessary complication aimed at reducing startup emissions. On most trucks I have seen with SAI (not many), Land Rover put SAI in and removed the oil cooler. If I had to choose I'd take the oil cooler.

You can remove the SAI but your ECU will probably be looking for it and tell you there is a problem (even though there isn't). A non SAI ECU doesn't look for it and doesn't throw a code. You just take everything out and seal the four holes in the heads. Some state inspections may take a dim view.

I have the same dangling radiator connector. Makes no difference that I can tell.

 

Ok, that answers my biggest question. I just wasn't sure what effect that was having. Thanks.

 

That sensor is referred to as the "thermostat monitoring sensor" and happens to be installed on vehicles with SAI.

Questionable whether it has anything to do withe SAI? As others repoeted no SAI codes if that sensor out of system. Possible to get/see P0126 if dangling? ......

 

Ah. That's why there is no issue with it being disconnected. Presumably the Sai never comes on.

 

SAI should still come on & work as advertised with that sensor disconnected.
......

 

I own a 2001 Discovery and the secondary air pump doesn't work.

I connected the pump directly to a 12 volt source and the pump works

What are the possible causes for the pump failing to come on causing a code?

 

I was surprised how many issues I used to have that were resolved by checking and replacing fuses. Have you run through those yet?