No, not misleading at all. I really appreciate the input... Going to try and get to the bottom of this over the weekend.

 

I took the same measurements just now on my '02 V6:

The two smaller (supply) lines were about 190.

The larger (common return) line was about 120.

The ambient temp was 50 degrees.

The car was fully warm after a 25 mile drive.

The radiator inlet (measured directly on the tank, not the hose) was 200.

The climate control was in Auto, set to 75.

The dash center duct temp was 105.

Shoe size: 13W

MaryAnne.

Hope this info helps.

How difficult would it be to jumper the aux coolant pump?

 

Thanks. This was helpful.

My son came home after going to the gym this morning (5mi each way) runs in and says "Dad, heats working". I go out 20 mins later and ambient air again..

Here's what I have now and I have to tell you all these readings are pointing (I think) to a faulty thermostat. (I have aluminum housing)

Ambient Temp - 55 degrees

Car Fully Warm

Cooling Fan - running on low speed (normal on V8)

HVAC set to "hi"

Temps @ idle:

Upper Hose @ Rad - 187 deg
Lower Hose @ Rad - 162 deg
Upper Hose @ Thermostat Hsg - 189 deg
Lower Hose @ Thermostat Hsg - 172 deg
Thermostat Housing - 187 deg

Aux Pump - 166 deg (both sides) - no surprise here! (Not operating)

Hose coming off upper rad hose going to DCCV - 178 to 180 deg

Post DCCV - both hoses - 175 deg
Post DCCV - large hose -182 deg

Temp @ center vents - 115 to 119 deg, same with floor vents.

Drove car around the block and initially the heat boosted up then was 110 deg when I pulled car over to check.

Now IDS showed 194 deg temp at idle the other day. It seems low but pretty much lines up with the ir temps I pulled this morning.

All the temp readings seem low. It would explain why it takes forever to get heat.

So:

DCCV is operating (well, at least the solenoids are open at this point) and AC works when set to 65 on panel.

Aux Pump still not working. Must be an electrical issue. Not sure if aux pump can be jumped. At this point not a show stopper for me. (Maybe ground wire is broken - couldn't trace it as extensive as the power side) Not sure if CCM commands it or PCM.

Heater Matrix is not blocked. PHEW!!!

Guess it's time to replace the thermostat?

Get a genuine Jag thermostat, yes or can I get this sorted sooner by installing a auto box store type thermostat?

Once I get the thermostat out I can test it.

 

You can hot wire the aux pump to check how the heat in the car is.

OBD's ECT was saying the thermostat was OK I thought.

 

Thanks on info regarding aux pump.

Regarding the ECT - nothing was flagged but engine temp showing 194 deg. That seems rather low. Even 200 deg.

Would a code set if coolant temp is too low? Just curious..

 

A few quick thoughts. Heading out to breakfast with the grandson in a few minutes. More verbose details later.

I don't think the coolant temps you recorded are that low. That was my hunch YESTERDAY. This is today. The winds have shifted. I noticed a reading on a rubber hose was about 10 or 15 cooler than a reading on metal. If that was the case, your coolant temp at the radiator inlet was comparable to what I recorded.

I also think the inop aux pump must be a big part of the problem. I'll have to look through the wiring diagrams, but there's got to be a way to jumper it for troubleshooting. If the pump only has a power and ground, disconnect the connector and run a pair of wires to the pump, just like how you previously mentioned bench testing it.

And most importantly, tell your son he is busted and should treat your car more gently. The aux coolant pump increases coolant flow through the heater at low RPM. Suddenly your son gets heat, when you did not. What was different? How about his right foot?

 

Might set a code then, but would want a big discrepancy as I recall reading.

JTIS only seems to document the thermostat behaviour for the 2002.5MY+ models but if the 4.0 is similar then the car's aiming for above 180F, probably more than 190, but up to about 216!

For hot air via DCCV you don't need particularly hot coolant, though (at least, not on the STR).

With the aux pump not running I expect what happens is that the small flow just doesn't provide enough heat to the cabin.

 

Your wiring diagram is here, courtesy of Gus. Section 6.1 for the aux cooling pump:

http://www.jagrepair.com/images/Auto...01999.25en.pdf

At the front power distribution box, remove relay #5 and check for +12V at sockets 1 and 3. Those both come from fuse #1, which you previously mentioned checking. This is unswitched battery power, so the key position doesn't matter.

If you've got power at both sockets, run a jumper between sockets 3 and 5. Your pump should run. If not, you've either got a bad pump or a wiring fault from the relay to the pump, or from the pump to ground.

If the pumps runs when the relay is jumpered, try a test drive. I expect you will get nice warm heat. From there the next step will be to determine why the pump wasn't getting commanded on. I think you mentioned you'd already swapped the relay with a known good one. Swap the one currently in #5 to another position and make sure it hasn't failed. I think the front fog lamps use the same relay in position #7, so that would be a good test.

And the grand finale: If the pump runs with relay #5 jumpered, and the relay is confirmed good, then your Air Conditioning Control Module is the likely culprit. The ACCM provides a ground to relay socket 2 to command the pump to run. It's possible the ACCM is not getting an input to cause the ground output to the relay, but that's a whole nuther can of worms. Try the jumper and voltage tests at relay socket #5 first and let us know what you find.

 

Hi Karl,

I'm OK with electrics not proficient so bear with me as I hope I transposed your directions correctly. I pulled relay #5 - tested for voltage between pins 1 and 5 and 3 and 5.

Both showed 12.50V

Disconnected aux pump connector and plugged into my old aux pump and installed a jumper between pins 3 & 5 and aux pump ran.

I swapped out Relay #5 with Relay #7 and fog lamps still work so we can rule out the relay.

So, looks like I am going to have to find another ACCM. I suspected this as a potential culprit as well (I referred to it as a CCM) but ACCM is correct.

I guess my old DCCV leaking contributed to drawing too much current causing the ACCM taking a dump.

At the end of the day I'd rather swap out a ACCM instead of the DCCV again...

If I get a chance tomorrow I'm going to pull the ACCM out of the car and take it apart to see if I see any burnt traces on the circuit board.

I took apart the other ACCM the other night (for practice) and the board looked fine but IDS flagged it with a code when I had it hooked up to the car. (internal CCM fault)

Thanks again for all your help!!!

 

This would be my course of action.

 

Groovy, sounds like you've made some great progress.

Did you check for heat while the aux coolant pump was running?

Did you son ever admit to "spirited" driving?

If you really want to move into overkill territory, there's one more thing you can try before replacing the ACCM. With the ACCM disconnected but the relay installed, ground the pin at the ACCM connector for the wire running to the relay. (Sorry, typing on my phone so can't access the wiring diagrams)

With this wire grounded, that's the same as the control signal supplied by the ACCM. The pump should run. This will help rule out anything weird like the relay not making good contact when installed, or a wire fault between the relay and ACCM.

 

Haven't had any time to look any further on this. My brother in law had his car (09 Altima) towed to my house for the dreaded electric steering column lock failure) I was able to sort that out by prying the case apart and removing the spring which activates the steering lock. Much better solution than spending $1,000 and now it will always start.

Anyway. I took the jag out this morning. I noticed it took almost 15 mins for the needle to get to the midway point.

Seems like a long warm up time to me as I know this cars behavior very well. Also it seemed to take a while to go from 10 o'clock to 12 o'clock positions on temp gauge.

Awaiting a replacement ACCM for install but I'm wondering if the thermostat is also contributing to the heating problem. (I think it's an aftermarket brand that came with the aluminum housing)

Any feedback would be appreciated.

 

I think you (meaning owners outside UK/EU) may be finding such things are not possible on S-Types because they have immobilisers (by our laws) that are very hard to bypass.

The good news is the cars are hard to steal/hot-wire. (Which is what our laws sought to achieve due to the large numbers that used to be stolen.)

 

Fifteen minutes seems way too long. On my '02 V6, the needle is centered within five minutes after a cold start.


Sounds like you do have two issues going on at the same time. However, I wonder if the aux pump doesn't get a command to run until the coolant registers as warm enough to provide heat? The heater fan is the same way. In auto, the fan runs very slowly (or not at all) until the coolant has warmed up somewhat, then the fan kicks on.


Back to the temp gauge, I can't remember if it was in this thread, but keep in mind the needle is deliberately misleading in the middle of the temperature range. Anywhere from about 180-240 or so causes the needle to center. Any fluctuations within that range are hidden. So if the needle was at the 10:00 position, the coolant must have been well below 180 still.

 

Hi Karl,

Yes, my S Type is the same. Needle goes to center within 5 minutes at most from a cold start. It took way too long to get to center.

The car was off for about 45 minutes today after a 30 minute drive (local/highway) and when I went to restart it the needle was below the 10 o'clock position again... (between cold and center) and took another 10 minutes to literally crawl to center or slightly off center (below center) definitely something is off with the thermostat I fathom.

I'm fully aware of the "idiot Jaguar center gauge" as I refer to it as...

I also have the same when turning the climate control on - no fan until coolant warms up then heater fan eventually kicks in. Not now, as soon as I turn on the car and turn on climate control full fan speed.

I just jumpered the aux pump in the car since the car was fairly hot after driving around for 35 minutes. Pump came right on I could feel and hear it. Took her for another 20 minute drive, little difference in temperature output. (felt a tiny bit warmer but not much and the DCCV is still plugged in though - couldn't get to the plug and don't have time to start removing the aux pump and intake hose to disconnect)

So, I think the ACCM is just sending random signals all over the place with vents, DCCV, no aux ground, etc and I suspect the thermostat is also stuck open... hence, the multiple lack of heating issues and an open thermostat would be more prevalent in colder conditions than warm temps. Today is a very cold day here (35 - 40 degrees)

I personally think the ACCM is beyond the trace issue (haven't inspected the board yet) and the CPU on the board is simply done.

I have another ACCM on the way and I'm ordering a Jaguar thermostat now.

I don't like throwing "parts" (thermostat) at an issue but I suspect the thermostat has given up the ghost and is worth changing at this point anyway and the ACCM is definitely done, which I had a sneaky suspicion after finding coolant in both solenoids on the old DCCV after removal and inspection. I thought I lucked out with the ACCM but not...

For the cooling system in general, No leaks now, holds proper pressure and coolant level in tank (replaced expansion tank, hoses, radiator fan, radiator and DCCV/aux pump) and was properly bled via JTIS procedure after each job requiring opening up the cooling system.

 

Definitely not possible on the S Types but yes to Nissan I guess.... He just picked his car up so I can get back to my own S Type woes...lol

 

Is the low and slow needle a new symptom? Assuming (Danger! Danger!) the gauge is accurate, that would certainly point to a bad thermostat. What does your scanner show when the needle is showing left of center? How about an infrared thermometer at the radiator inlet under the same condition? Previously I thought the thermometer reading was pretty close to normal, so this sudden change is interesting.

When the new thermostat arrives, how about removing the old one and test them simultaneously in a pot of water on the stove? You could get a lab coat and a clipboard so you'd look all scientific.

As cheap and lazy as I am, I'd be tempted to try just the thermostat first. For all we know, if the coolant never got hot enough due to a bad thermostat, the ACCM may have never received the proper input and thus never commanded the aux pump to run. It wouldn't hurt anything to try.

 

I will do just that (minus the lab coat...lol) thermostat and o ring seal (I have the aluminum housing) are slated to be in on Fri.

It could possibly be another symptom pointing to the thermostat...

Typically I have seen my temps between 205 - 215 degrees at idle on IDS in the past and 198/200 - 206 degrees when car is moving.

Now it's fluctuating between 185 - 195 degrees. (seems to settle in the low 190's at idle.)

I'm going to use the car tomorrow and monitor temp via IDS from cold and time it to see how long it takes to get up to operating temp. (I guess 190 deg at this point)

Looking forward to getting to the bottom of this in hopes it helps others in the future.

Thanks for your input.

 

OK, had time to mess with this today.

Used CCM arrived today.

I first removed the thermostat and tested alongside the replacement.

It was indeed "lazy". It started opening early at 165 deg F and was fully opened between 190 - 195 deg F, whereas when the old one was fully opened the new one was just proceeding to open.

Installed the new one and now engine temp averaging between 200 - 210 at idle.

Problem - Part 1 resolved!

Now to Part 2

Now after letting the engine warm up and of course trying to purge the air pockets I felt the DCCV metal lines by hand (all 3). I was able to grab them and hold onto them so clearly the DCCV solenoids must be stuck closed.

Disconnected the DCCV harness and turned on climate control and same - no heat, Again, I can hold the metal heat lines. I'm sure the temperatures I was obtaining on the lines early on were carry over heat from the exhaust manifold.

I tested for power at the DCCV harness - center pin on the DCCV to vehicle ground and saw 12.56V.

Could not do any further testing as the DCCV is in "never never land" in the engine bay. (although I did get a small hammer to hit the top of the solenoid cases) - no change.

Installed the used CCM and same issue - no aux pump operation and DCCV output is 0% both sides on IDS. Now, I think when full cold (AC) is requested the solenoids are shut (0% output) and no aux pump operation. (Going to test this on my 2004 XJ8 to see if these results match what I observed earlier.

Now, what does this mean for power output from the CCM if the solenoids are stuck closed and CCM is commanding them to be opened to allow coolant flow? I do not believe there is a wiring issue from ACCM to relay or DCCV.

I also checked the ground for ACCM (adjacent to ABS/DSC unit - clean and tight)

I have a bad feeling I have a bad DCCV also, ugh. (stuck closed)

The bright side is I identified a lazy thermostat but it looks like I need to order another DCCV. (Bosch? but I heard they are problematic) what about Motorcraft brand for the Lincoln LS?

Thoughts?

 

Just as an FYI - the needle on our "Jaguar Special - idiot needle gauge" gets to center right at 170 deg F (on the 4.0 V8 anyway) and stays put at least through 220 deg F. (As IDS showed that temp upon initial run with air pockets not bled)

Watched the needle gauge position while hooked up to IDS.

With new thermostat took about 5 minutes to get to center on gauge.