Driving for a day trip and temp is normal ~200° range. Ran some errands around a town and noticed that twice, the UltraGauge indicated “err” for the engine temp section. Other gauges are providing data just fine in real time, and the temp gauge on the dash reads normal. No codes or SES light.

Both times, I powered off the engine and the temp was displaying again after I fired it back up, but the same thing happened again about 10 mins later.

Anyone see this before? I read up on bad coolant temp sender symptoms, and this does not appear correct. I will fully unplug and reconnect the UG in the meantime but wanted to see if anyone had input as well.

Thanks!

 

as a precaution, when the truck is cold, unplug the UltraGauge and using electrical contact cleaner spray out both the OBD2 port and the UltraGauge plug.

look for any green corrosion on the pins and receiver.

 

I will check but seems unlikely. The rest of the gauges were reading in real time and the UltraGauge itself is only like 3 months old.

 

Maybe sensor is bad or going bad
My first ug lasted 4 years then the wiring started to go bad at the port

 

Reads in the middle position as expected based on engine temp when the UG quits.

If I recall, symptom of bad sender is high temp light and low reading on gauge, along with a code. Dont have either of those.

 

My UltraGauge would read error on engine temp for a while intermittently as my CPS sensor was on its way out.
I would be driving- sometimes I could feel the truck make a slight hiccup/ error would read on UltraGauge / and i could cary on driving without any problem.. Got to the point where I would reach under plug/unplug from OBD2 & it would re-register ridding err signal.
Fast fwd a few months & hiccup slowly progressed & the truck would randomly shut off (stop light, slow crawl, in traffic) I began to think humidity or weather had some relation to it... However each time it failed - Err on temp UltraGauge.

And because I replaced CPS with a non bosh unit- this symptom of err on gage came back several months later in the same fashion. no hiccup turned to slight hiccup turned to Random shut off again..
i replaced CPS sensor with OeM, and it’s rid itself of all above symptoms.


One things for certain: It was eventually clear that hiccup while driving was interrupting my OBD2 reading/connection (thus error; and it was always only the engine temp, which is water temp on UltraGauge reading) - in my case the symptoms wound up being clear it was CPS & this fixed it.

 

Thanks Randy - this is perfect. I’ll swap out the CPS when I get home. You said that this behavior persisted for a few months before the CPS totally failed, correct? I’m about 200 miles from home at the moment.

 

In my case, I had months, where it would act up from time to time. Then nothing. Then I’d have a random misfire feeling while driving- I’d see err on UG.

On account of knowing Now I had an issue with CPS, and that my UG was acting up & giving me a err reading in the temp sensor spot - felt easy to make that correlation afterwards.

I doubt it’s a code for a bad CPS- just sharing.

 

Hmm. I don’t know the history of my CPS - but it’ll fail eventually. I don’t have any symptoms yet aside from the “Err” message. Seems reasonable to replace the sensor proactively (especially since I already have the part) since there are 0 other symptoms to troubleshoot - I could start messing with ignition coils etc but I figure I’d at least have some misfire codes if it was something of that nature.

I guess another possible cause is a bad battery connection or bad ground somewhere that’s causing an imperceptible problem that kills the coolant temp feed... I’ll check the battery terminals as well.

 

Just wanted to post an update on this in case anyone comes looking in the future. I only saw the "Err" symptom when driving on surface streets in stop and go traffic - on the highway, it worked fine. I suspect that in the slower conditions, there was less airflow and the CPS was getting hotter, causing intermittent connection interruptions that were enough to throw off the Ultraguage, but not enough to impact the driveability of the truck. From what I understand, usually when the CPS goes, it's a result of heat.

I swapped out the CPS with a new Bosch part and have not seen the "Err" symptom since.