Coolant temp sensor

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I guess the ecu sensor feeds the engine temp to the engine ecu, which tells the auto ecu to hold gearshifts longer to allow the engine to heat up faster from cold, at a guess anyway.
However i will get one and bung it in and see how it goes.
Thanks guys for your input, i will let you know what happens.
 
Grit Valve said:
The log book says other wise I know the head has been changed but no extra wires I. The loom for the third sensor the black aircon one
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My log book says mine is a 99 and that doesn't have the third sensor either. Just means it was made 98 first registered 99. The head is not a problem if it has an earlier head on it. But unless they changed the loom as well it can't be a MY 99 model.
 
wammers said:
My log book says mine is a 99 and that doesn't have the third sensor either. Just means it was made 98 first registered 99. The head is not a problem if it has an earlier head on it. But unless they changed the loom as well it can't be a MY 99 model.
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Isn't the plastic manifold and egr count for that then? And the egr Solinoid valve attached to the bulk head.
 
spadgr said:
I guess the ecu sensor feeds the engine temp to the engine ecu, which tells the auto ecu to hold gearshifts longer to allow the engine to heat up faster from cold, at a guess anyway.

However i will get one and bung it in and see how it goes.

Thanks guys for your input, i will let you know what happens.
Click to expand...
.

Correct, the engine's ecu coolant sensor signal is sent to the gearbox ecu from the engine ecu via the CAN-bus. This sensor has nothing to do with the temperature gauge, so a flickering temp gauge is not related to the gearbox problem, so don't waste your money on another temp gauge sensor.
If the gearbox is defaulting in to 3rd then my advice would be to get a fault code reader and read the codes out of the gearbox ecu.
 
davidg said:
.

Correct, the engine's ecu coolant sensor signal is sent to the gearbox ecu from the engine ecu via the CAN-bus. This sensor has nothing to do with the temperature gauge, so a flickering temp gauge is not related to the gearbox problem, so don't waste your money on another temp gauge sensor.
If the gearbox is defaulting in to 3rd then my advice would be to get a fault code reader and read the codes out of the gearbox ecu.
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There is no CAN Bus on a P38 diesel, nor on the V8 4.0 as far as I'm aware, only on the 4.6 with the ZF4HP24 gearbox.
 
I took the rangey to an auto specialist, and he scanned the vehicle. He drove the vehicle till the fault occured and recorded the live data. At the time the fault was occurring, the engine temp was erratic, sometimes reading as low as -41 degrees. This ,he said, would cause the lock up to drop out, and en extreme cases of low temp readings could cause the auto to drop in to 3rd.

Both he and i scanned the auto and it spat out no fault codes.

I will hook up my faultmate and drive the vehicle till the fault occurs and see for myself what is happening with the engine temp.

I will keep you posted.
 
spadgr said:
I took the rangey to an auto specialist, and he scanned the vehicle. He drove the vehicle till the fault occured and recorded the live data. At the time the fault was occurring, the engine temp was erratic, sometimes reading as low as -41 degrees. This ,he said, would cause the lock up to drop out, and en extreme cases of low temp readings could cause the auto to drop in to 3rd.

Both he and i scanned the auto and it spat out no fault codes.

I will hook up my faultmate and drive the vehicle till the fault occurs and see for myself what is happening with the engine temp.

I will keep you posted.
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There is certainly a different change pattern on my diesel when it's very cold, it hangs on to the lower gears longer, however I have not really established how this is done.
 
Datatek said:
There is certainly a different change pattern on my diesel when it's very cold, it hangs on to the lower gears longer, however I have not really established how this is done.
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Think he needs to establish which sensor he is reading. I would not think the one he was looking to change, the single wire gauge sensor has anything to do with gear change. However the ECU temp or inlet air sensor which effects fuelling may. If he has a single wire gauge sensor it must be a pre EGR engine or at least should be. So the ECU preset of -38 should not be there for inlet air. So the fluctuating reading of as low as -41 must be coming from either the air inlet sensor or the ECU sensor. The gauge temp sensor is not in any way connected to the engine ECU so on live data from engine ECU that sensor cannot be read.
 
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Datatek said:
There is no CAN Bus on a P38 diesel, nor on the V8 4.0 as far as I'm aware, only on the 4.6 with the ZF4HP24 gearbox.
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Ooops yes, you are correct the CAN-bus did not come out untill 99MY with the thor engine. There is an diesel engine ecu multiplex signal output for the gearbox , but I don't know what the signals that it carries are.

If you think that the engine temperature sensor is causing the problem then disconect the sensor. The engine ecu will then default to a value of 50C (do this with the engine warm so that there won't be a starting problems). Then drive the vehicle and see if the gearbox problem is fixed. The engine ecu will log a fault code for this, but at least you can eliminate the sensor.
Also if you have a fault code reader is there an out of range fault code for the temp sensor in the engine ecu?.
 
I disconnected the single wire temp sensor at idle when the vehicle was warm and the temp gauge went to cold. If this sensor was at fault then when the auto was playing up the gauge would also fluctuate and i would have noticed, so i am guessing its the edu sensor.

I have found a new one on ebay for 15 quid so will bite the bullet and see what happens.

Also going away fishing for a few days. This involves towing a boat for @600kms (brave, i know), so i will take the fault mate, as its bound to play up, although i have cleaned all the electrical terminals on the suspect sensors.

I am tempted to pull the engine ecu plug and clean it up before going away. Any risks involved in that?

cheers
Spadgr
 
spadgr said:
I disconnected the single wire temp sensor at idle when the vehicle was warm and the temp gauge went to cold. If this sensor was at fault then when the auto was playing up the gauge would also fluctuate and i would have noticed, so i am guessing its the edu sensor.

I have found a new one on ebay for 15 quid so will bite the bullet and see what happens.

Also going away fishing for a few days. This involves towing a boat for @600kms (brave, i know), so i will take the fault mate, as its bound to play up, although i have cleaned all the electrical terminals on the suspect sensors.

I am tempted to pull the engine ecu plug and clean it up before going away. Any risks involved in that?

cheers
Spadgr
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Think i have been trying to tell you that for a while now. ONLY the ECU temp sensor or the Air inlet temp sensor are being read on engine ECU live data. The problem HAS to be one or the other it CANNOT be the gauge sensor. Get proper diag on it, Snap-on are not reliable on these cars. If you pull the ECU plug make sure the battery is disconnected first.
 
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wammers said:
Think i have been trying to tell you that for a while now. ONLY the ECU temp sensor or the Air inlet temp sensor are being read on engine ECU live data. The problem HAS to be one or the other it CANNOT be the gauge sensor. Get proper diag on it, Snap-on are not reliable on these cars. If you pull the ECU plug make sure the battery is disconnected first.
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As above, Gauge sensor ONLY does the gauge.
 
spadgr said:
I disconnected the single wire temp sensor at idle when the vehicle was warm and the temp gauge went to cold. If this sensor was at fault then when the auto was playing up the gauge would also fluctuate and i would have noticed, so i am guessing its the edu sensor.

I have found a new one on ebay for 15 quid so will bite the bullet and see what happens.

Also going away fishing for a few days. This involves towing a boat for @600kms (brave, i know), so i will take the fault mate, as its bound to play up, although i have cleaned all the electrical terminals on the suspect sensors.

I am tempted to pull the engine ecu plug and clean it up before going away. Any risks involved in that?

cheers
Spadgr
Click to expand...

No risks as long as you disconnect the battery first and use eletrical cleaner your be surprised how clean the the connectors are , you need to release the lock at one end before you try to separate the connector .
 
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