Hi.
I'm struggling with a very odd problem.
My recently purchased Jag X-Type's temp needle is showing me an overheating, but no warning is shown.
I think I've done everything, but didn't manage to fix that.

Issue:
- Problem may be reproduced only after the long idle period! I assume it is related to heating of some elements.
- So, after starting the engine in the morning - temp needle is slowly going to the H mark and beyond. Lays almost horizontally.
- In the meantime, no warnings are shown.
- Checking the temp with the ELM scanner shows nominal temperature (90-94C).
- After 1-5 mins (depending on the external temperature) temp needle starts to leap furiously up and down and after some time it settles on the central mark.
- Since this happened - no issues with the temp indication are observed until the engine cools down.

Things that have been done:
- New battery installed. Voltages are 12.9 - 13.1 / 14.8.
- Thermostat replaced (Gates). Twice actually.
- Temperature sensor replaced (Mazda B593-18-840A, with the grey connector).
- Temperature sensor connector cleaned.
- Coolant system cleaned.
- Coolant replaced (HEPU P999 G12).
- Coolant expansion tank replaced (Polcar).
- Coolant expansion tank cap replaced (Vernet).
- Water pump replaced (SKF).
- Tried to disconnect Temp sensor while the issue is observed. Needle goes to C mark. After connecting - straight to the H+.

I have no idea what to do next.
Any advice?
Thanks!

 

@Thermo , could you please check my issue?
I'm desperate in fixing it. Hoping for your "guru advice".
Thanks!

 

Maybe relatd, maybe not.

My 2.1 "big Block" of 2009 build did that a while ago. Temp gauge very unstable, and the fans on/off all the time. The engine was NOT overheating in any way.

New Temp sensor, worse, oops, at least something.

Mazda sensor, as yours has, read too cold.
Damn, beer o;clock.

Next day, clear head, has to be the sensor, as it tells the ECU what position the needle is to be at.
My V12 brain took over, coz they have issues with the ECU CTS unit, and the engine shuts down, oops big time. A GM sensor fixed them all, and is proving very reliable.

In my stash, I had a NEW AJ16 sensor from the X300, same threads etc etc, but different plug, not the end of the world.

The specs of the thing were the same as the X spec sheet I had.

Fitted it, whoopee, all sweet, and the car has no idea its an alien part. The needle is just shy of the centre line, and the engine is happy, and the fans do what the should.

Hope yours is that simple.

Forgot, 3 Gen Jag sensors I got were all over the shop, so there is a Gremlin somewhere in the Parts Supply System, me thinks.

 

TIE, like what Grant said, your problem is the coolant temp sensor. It is possible you got a wonky temp sensor from the store (as much as we would like to think a new part will work perfect, sometimes it is not the case). Working with temp sensors at my work, you have to know what the shape of the resistance curve is. The car is programmed to take this into account. Different shapes will cause the indication to do interesting things. I would say to start with replacing the temp sensor again and if at all possible, get the jaguar part (atleast one from a 3.0L Lincoln LS - that is a very similar engine and shares a lot of the same parts). Lets see what you have at that point and then we can take things from there.

The only other thing that I can say is you need to look at the wiring near the sensor. Does it appear to be damaged? If you see exposed copper, that could be causing it to ground out some and cause the temp reading to read a little high. If you see damage and are not sure how to fix it, let me know. i have a few tricks for you.

 

Can you please confirm that I need to purchase LNA1600AA temp sensor? Cos I'm offered with a tone of the aftermarket options.

And here is the video of the issue: https://drive.google.com/file/d/1kz7...w?usp=drivesdk

 

https://www.partsgeek.com/yqv9mbh-jaguar-x-type-water-temperature-sensor.html?utm_source=google&utm_medium=ff&utm_co ntent=DN&utm_campaign=PartsGeek+Google+Base&utm_te rm=2002-2008+Jaguar+X+Type+Water+Temperature+Sensor+APA%2F URO+Parts+02-08+Jaguar+Water+Temperature+Sensor+2005+2007&gad_s ource=1&gclid=CjwKCAiAhJWsBhAaEiwAmrNyqwJObFaP_x7T w6Qi539bl4HWcTukXy7I2ywdYjVlC1V-pOC9EstuEBoC6csQAvD_BwE

https://www.google.com/shopping/product/1?q=%22jaguar+x+type%22+coolant+temperature+sensor &client=ms-android-att-us-rvc3&sca_esv=593086963&biw=320&bih=526&tbs=vw:l&pr md=sivnmbhtz&sxsrf=AM9HkKngf3b9tJubd2ZzYSCJpdKF9CT 27w:1703252410770&prds=num:1,of:1,eto:181185014503 63595292_0,prmr:1,cs:1

 

Coolant Temp Sensor = LNA1600AA =M12 threads. This is the one up top, and easily damaged when removing the Inlet for sparker changes. Listed in the Cooling System Section of teh Parts Book.

Temp Sensor = LRA1600AA s/s many times to XR858700 = M18 threads. I know not where this sucker is, BUT, some scribes I have read "claim" it is an Oil Temp Sensor, and I have NOT yet found it on mine. If that is true, then the oil filter housing would be my best guess. It is listed under Engine Management Sensors in the Parts Book.

The fact the LRA????? changes numbers 4 times, has my old Parts Management brain smelling some issues with it, dunno.

 

Nope.
Installed 2x sensors. One from denso and one original jaguar (the same denso, by the way).
Issue persists.
Dash panel checked - everything is fine.

I believe the issue in the ECU. Dried electric capacitors or so.

 

TIE, if you have failed capacitors in the ECU as you say, then there is only 1 fix, replace the ECU unless you can do circuit board repair and can get new caps that are recently made (certain types of caps do have a lifespan and do dry out over time). But, that is not a skill that a lot of people have. I would be taking the wiring going to the temp sensor and bending it over a long thin screw driver. What you are going to do is run the wiring around the screwdriver shaft perpendicular to the shaft. By running the wiring about 180 degrees over the shaft, as you move the wiring over the shaft, if you see the wiring make a goofey bend (it will tend to kink, not be smooth), that would indicate that you have somehow damaged the wiring inside the insulation. This can cause intermittent issues.

 

TIE, your original post said the scanner shows the correct coolant temperature. Have you confirmed the live data from the scanner is normal and stable even when the gauge is acting wonky? That doesn't seem like a sensor problem if the ECU reports the correct temp. Unless as thermo points out it is an intermittent problem. The scan data is very slow compared to the speed data is actually processed in the ECU so I could see the scan data looking different than gauge data if the sensor or wiring are intermittently bad.

 

Yes, live is normal.

 

TIE, if your live data is matching what you can measure using non-car systems, then that really only points to your instrument cluster having issues. What a scanner would read is what is put on the data bus and all systems in the car would see that data, along with the instrument cluster. So, if the instrument cluster is doing something different, then your problem is isolated to a single component.

 

Our X-Types have issues with electronics.
For example, transmission issues may be related to the corrosion in the TCM PCB. Moreover, it is temperature dependent (due to physics).
That seems to me very much like my issue, but with relation to the ECU PCB. Cos I don't think that Dash sits on CAN. And corrosion on the Dash PCBs are less possible. I suppose there are analogue signal for needles step motors from ECU.
Anyway, I'll start with cleaning ECU and replacing CAPs.

 

TIE, the instrument cluster does sit on the CAN bus. IT is also the gateway to get information over to the SCP bus (GEM module and Nav unit info) and to the D2B (audio) bus. There is a lot of info travelling through the instrument cluster. I pulled this info from the JTIS program which is very informative on the systems in the X-Type.

 

Hi Thermo.
I've finally found a good specialist.
So, in my ECU there were Electrolytic caps dead, SMD caps dead, couple of diodes dead and several soldering points cracked.
Engineer said that that was a cause of the issue.
I'll test if the fix helped in winter.

To sum up, it is a good idea to replace Electrolytic caps in as many units as possible (TCM, CU, ECU, FCM,...). Small caps have just 1000 hrs of the operation time and some of them may be heavily degraded by 50 000 km.

 

Sorry for arriving a little late to the party. 12 years ago, started the engine & the coolant temp gauge maxed out & the warning light came on too.
I knew it was lying because the engine was cold after running only a minute or two.

Every water temp sensor can be easily tested if you can find a data sheet. Some have a positive temp coefficient- meaning resistance goes up
as the temp increases. Others have a negative coefficient which do the opposite. All you need is a simple volt-ohm meter to check the resistance
& test without removing the sensor.

Turned out my problem was a chipmunk. Little sum-you-know what decided to make a nest next to the coolant sensor. Apparently the wires
looked appetizing & the little bugger ate through the two on the connector. Don't recall if the wires had shorted. Simple fix: the neighbor's cat.

An open/bad connection/open sensor implies an over-temp condition. Try disconnecting the temp sensor connector on a good sensor.
Gauge should max out & the red over-temp light should come one.

Couldn't locate a data sheet, so just checked the resistance on mine (2004.5 Sport) using a VOM.
Disconnected water sensor connector when cold. Measured roughly 2k ohm resistance.

Started engine. All looked normal as it warmed up. Disconnected temp sensor while it was hot with engine
still running.

BTW, If you do this, I assume you know everything there is to know about safety around a spinning serpentine belt
and a running engine.

Measured roughly .6k ohms (~600 ohms)- a negative temp coefficient.

Red light didn't come on at first, but after the gauge needle slowly maxed out, the red over-temp light lit.
Was by myself, so not exactly sure how long it took- wasn't long.

Believe you said, no light- could be burned out (doubtful), but strange things can happen, if lets say the
sensor isn't totally open, but some other resistance.

What happens if the sensor is shorted or a low resistance to start?? Would appear it would also cause the
gauge to move to the right- how far? I don't know. With old analog gauges, we could actually calculate it
in the classroom- that was a long time ago.

Back in the day we would use 1/4 watt resisters & substitute them to troubleshoot a temp or fuel gauge circuit. Neighborhood Radio Shack had everything....

In this case, I would disconnect the connector & insert a 2k ohm resister in the female end of the connector & look at the gauge. This simulates
a cold (~70 degree F) engine.

Would then pull out the 2k ohm resistor & plug in a 680 ohm resistor & see if the needle goes to midrange and then start troubleshooting from there.

I don't mind helping anyone, but last time I offered assistance to someone by PM, I got in trouble.

Not surprised reading about bad ECU caps. Happens in older Fords & Toyotas all the time. Used to diagnose/repair things when mechanics got in
trouble like this for fun. To me, it's like doing a crossword puzzle or crytoquote.

Used to be able to buy kits with enough capacitors to replace the caps in an ECU. Electrolytic capacitors leak- it's a fact of life.

Here's a typical Ebay kit link for a Toyota/Lexus:
https://www.ebay.com/itm/27574717056...8aAvL-EALw_wcB

First ECU no start problem brought to me: a guy had a Mustang II- in several shops for over a year. He needed to move & needed to fix the car or sell it. Had 3 problems.
Shorted diode in alternator that drained the battery in 3-4 days. (easy)
Bad distributor bearing- not related to no start. (easier) Just seemed odd to me to see the distributor rocking.
Leaking caps in the ECU. This killed the PWM signals going to the fuel injectors & fuel pump.
Used an scope on that one to see the pulsed grounds coming from the ECU. (required getting out the big gun (scope)

A <$20 capacitor kit brought it back to life.

If you wanna take a walk on the wild side, remember to observe polarity on the capacitors. Believe you can still get kits. Despite seeming like rocket science,
no engineering degree required. I don't see one for the X-type- but it is still a Ford- as so many true Jaguar owners tell me....

But if you don't or can't desolder/solder- this is not the time to practice.

Cold solder joints/temp-related intermittent connections make the best technicians start talking to themselves. I have 50+ years experience. Started back when
we troubleshoot to the component level &actually repaired by replacing discreet components, like diodes, caps.
Nowadays, it's flow charts & then plug & pray... after replacing (see also easter egging) entire assemblies.

Good luck.

 

Thanks!

Regarding the advice. I don't think that there are any issues with the analogue part. Temp sensor is new and original.
Also, OBD2 scanner shows normal temperature while needle is in the red zone. And red overheating led is not lit up.
From these I can make a conclusion that there are issues with the packets, arriving to dashboard or with the dashboard (less possible as dashboard operates normally).
My theory is that Jaguar engineers created a separate packet for the temperature gauge at the dashboard and something going wrong with its forming inside ECU (some reference voltage is wrong). Cracks inside the solder (diagnosed) sounds wery much like a root cause.
Anyway, I have done everything I could. Let's wait for the winter