Just picked up a new AIM temperature sensor to read gearbox oil temp for my AIM MXG - this would be the X05NPTA4513BPRS sensor with the extended tip. Install was straight forwards, but I have noticed behaviour in subsequent days, and I'm unsure if this is considered "normal".

With the car cold and off, with a 12V supply of power powering the car's electronics, all of my other sensors appear to read correctly, showing fluids at between 26-28 degrees C, and air temp at around 20 degrees C. In contrast, the X05NPTA4513BPRS sensor is showing 46 degrees C, and can sometimes float up to 80+ degrees C while the electronics of the car are powered up, before dropping back down to 44C (with all other temp sensors reading in the 20's.

With the engine running, there are periods when the sensor will start reading in line with the other sensors on the car, but on my datalogs, it is still a little odd to see the temperatures being reported by the sensor being so far out of line with other sensors, and then suddenly start reading in line with the other sensors. Hard to tell what's going on.

Is there any debugging that can be done with the sensor? If I disconnect the sensor from the AIM, I immediately get negative values pop up on the AIM, but when the sensor is reconnected, it immediately goes back to displaying gearbox oil temp at 45C with the engine cold and off.

I am using the PT100 sensor calibration.

Am I looking at a sensor problem? Patch cable problem? calibration issue?

Link to the RS Analysis datalog. Pay attention to "Gearbox Oil Temp" to see what I mean. This datalog was taken with the car sitting at idle (not moving) on the driveway warming up. Compare it to "Rear Diff Oil T", which is a non-extended tip AIM temp sensor, and appears to be tracking normally, given that the exhaust passes next to the rear diff, so heats the oil up over time. The new sensor on the other hand appears to have a mind of its own for a while before suddenly getting with the program.

https://drive.google.com/file/d/18R7...ew?usp=sharing

Link to the MXG calibration -

https://drive.google.com/file/d/1ify...ew?usp=sharing

Offending sensor is on channel 8 - gearbox oil temp sensor.

I don't seem to be having the best of luck with AIM temp sensors. This will be the second sensor that is giving me issues.

 

I didn't look at the data logs. That is odd behavior. Can you swap the channel with another sensor to see if the problem follows the sensor?

If you got it from me, shoot me an email. I'll send another to help you diagnose what is going on.

 

No, I did no get it through you. I don't live in the US, but in Canada.

I removed the sensor from the transmission, and upon plugging it directly into the MXG just to rule out an issue with the patch lead, it reads now 324 degrees C, and fluctuates pretty wildly as I move the sensor wire around in front of the MXG.

I removed the sensor and plugged it into a different channel, this time for the other AIM temp sensor I have on the car that monitors rear diff temps. Upon plugging it in, it read 324 degrees again, which caused my MXG to trigger my rear diff cooler pump into action.

I suspect the sensor is yet another dud from AIM.. That would be the second one now that has failed in short order. Highly disappointing.

The disappointing thing is that the sensor did not even make it off my driveway before signing itself up for "Club Exit".

What are my options?

 

Before condemning the sensor, use stabilant-22 or equivalent on the 719 Binder connectors and swap the patch cable on your channel swp test to eliminate that.

Otherwise, send it in...

 

Good idea by Peter on cleaning the connector (I'd do all in the circuit).

I've had temp sensors fail, but never in short order. Most are 3-5 years old. Let me know if I can help - I ship to Canada (and the rest of the world) all the time.

 

David Clubine at Britain West in Brantford ON may be able to help.

 

Tried Stabilant 22A on all connection points, but no dice.

I even tried connecting it to the MXG directly on different channels directly off the main harness, eliminating the patch harness, and was seeing temperature readings of 324C as the sensor was resting in the palm of my hand, with wild fluctuations when I move the wiring of the sensor around.

Definitely an issue with the sensor.

 

My first one failed rather quickly also a few years back. You and Coach were helping me diagnose it back then. It was being used to measure oil temp. It had a slightly different failure mode though, and would display negative values on the MXG. I had since learned though that this is caused by an issue with the resistor within the connector. It's been sitting inside my desk drawer since.

Since then I made it a practice to wrap electrical tape around all connections in order to keep any hint of moisture out of them from road use. Purchased an AEM temp sensor instead, and all was good after.

Fast forward to today, and despite initially wanting to go the AEM temp sensor route again (and getting a quote from you for a custom extended tip sensor), I decided that it would be cheaper for me to stick with an AIM temp sensor. Now I'm hearing that saying in my head - "The poor man pays twice."

 

One of mine died at the transmission too. I ended up swapping it for a new one. AIM was nice enough to take the old one back and send me a new one (the sensor was about 9 months old). At the <$100 price level, almost worth it to keep one as a spare