Temp Sensors

Once the heater supply hoses I had a Check Engine Light which send me to the OBD II display where I found an Error Code 14. In the picture you can see that I have removed a section of the plastic cover on the passenger side seat. This is so I do not have to remove it each time I need to get to the OBD-II code display.

At this point, I know this about my Rover, my air condition cooling fans run all the time. Winter, summer, doesn't matter. They are on. In a normal situation they should come on when the air conditioner is used. They assist in moving air through the radiator especially at stops like traffic signals. And I had an Error Code 14.

With the Error Code 14 I had decreased fuel economy. I dropped about 3 mpg. And the Rover was very difficult to start when it was warmed up. One website had this for, Code 14 - Coolant thermistor Refer to test 14, continuity test procedure. And lastly I don't have anything in my manual about these error codes.

I was having trouble getting the information I needed from the various tech boards I check when problems seem to come up. The most helpful thing I got was, "run continuity test 14" from Hamrendan, Dan Hamren on the Land Rovers Only forum. This is good advice from a guy who knows his stuff. His truck is similar to Ozzie's at Ozzie's Offroad with a nice amount of tricked out stuff. But as it turns out no one really knew what that was. I didn't have it in my manual and never really got an answer from anyone. It turns out this must be checking the sensor with a volt ohm meter but I'm just guessing.

Let's start with a couple of pictures so we can all know what we are talking about.
Engine area
Close up, labeled
The hardest part of finding these parts is not having common names for the parts.

I called Motorcars LTD. to order what I thought was a failed sensor to fix the Error 14 problem. The gentleman there told me he didn't have any but he also told me the sensor I wanted to replace was just the sending unit for the so called "idiot light" and not the one that is related to Error 14. This sensor has a single pole plug. He also told me to hang a volt ohm meter across the poles of the other sensor I described and if it was open it was failed. It was open and thusly failed. He apologized for not having one. Ryan at Rover Cannibal recommended I go with new instead of used on this part. I was somewhat desperate due to loss in fuel economy and difficulty in starting the Rover when it was hot.

I called Atlantic British to get the part and tried to describe the part and location. I told him the code 14 story and he described a plug that was unlike any I was describing. I told him I had a pic. He told me the technician could tell us more. So I email the picture and named everything as I was able.

The next day he called me in the morning and told me the technician had my exact truck and told me that the temperature sensor I described and had tested was indeed the A/C fan temperature sender. He then went on to describe the plug again and it's location to me. He told me that was the sensor that had failed. As I described the plug to him, "as one resembling the plugs on the injectors", he said exactly. This is the plug fuel rail temperature sensor.

So I went out to the parking lot and sure enough there was another sensor behind the upper radiator hose right on the fuel rail, which is in the description of the problem. The plug was indeed the same as the injectors and guess what, it was unplugged. When I had removed the upper radiator hose I had unplugged it by mistake. The plug has a keeper on it to prevent this but I had broken the keeper 4 years ago when I was working on something else. I seated it and cleared the error code by disconnecting the battery for a few seconds.

I replaced the PRC 3505 temperature sensor. Lost a little bit of coolant. But not as much as I expected. Broke the hose clamp putting it back together. This just reinforces the fact that you need to replace any hose clamp you are working with. It did not change the condition of the fans being on all the time. There will be more investigation on this issue.

Problem solved. Good thing too because this fuel rail sensor is nearly a hundred US dollars. The sensor I purchased from Atlantic British was just about 30 US dollars.

The fellow at Atlantic British was awesome and very helpful. You can tell alot about what your working on by comparing the pictures that are online with the things you are testing. This will help you identify the part along with it's part number to your vendor.

Thanks for reading. And thanks to Atlantic British for the great information and help.

First rate, jolly good show.

Thanks for reading and happy Rovering.