code 6 tw sensor, coolant temperature sensor, part cross reference help please?

[obiwanwasabe]

Hiya,
The Beat has been fine lately, at least that is what I say when I am asked.
BUT today the mil (engine management) light came today on 20 miles from home, it drove back fine, temperature guage at normal, revs up to the limiter both on revs and speed, but the idle had gone up to 1700 rpm hot and 950 when it's cold. and interrogating the ECU threw up code 6 indicating the tw (coolant temp) sensor, which makes perfect sense to me. now, I'm presuming this is the one on the thermostat housing in the knuckle scraping space under the Dizzy!and is probably going to be a sod to get and will need ordering from Belgium or Japan. Does anyone know if this cross references to any other coolant sensor please?
I am also presuming that the dash guage is sensed elswhere as it is reading normal.
As someone is likely to mention check the ECU capacitors I have checked them and had a light and magnifying glass on them and they are like new, but if they need changing I still have a couple of uprated sets.
Any ideas?

Nick

[gymm]

Hi, message Steve_M on here. He has always helped me with problems I have had and has access to Honda data. I am sure he will see your post and advise but an inbox message is a little easier to find. Worth posting what you did to resolve it so others are aware. I am interested to find out what happens. Sorry I can't help more. Cheers, John

[obiwanwasabe]

Hi, Ta for the comment, as I find the cure I will post it. If I could reach the little beggar and also had some resistance specs on it I would put an ohmmeter across it but it looks like it is going to be as easy (read hard for that one!) to get it out as put the probes on it!
Tomorrows another day so may take it out then and test it in water heating up and have the probes on it to see if it does anything.
I would msg Steve but don't like to pester individuals so will happily await folks thoughts.
N

[obiwanwasabe]

OK, I've had chance to skin my knuckles now. first of all check a on diagnostic socket, bridgeing the twin plug covered by the yellow rubber cover, turn the ignition on and wait for the engine management light to blip the code, 6 short flashes confirms it is the tw (coolant temperature to ecu) sensor, this is located below the distributor and has 2 wires going to it, red/white and brown/ black, unplug it, with the ignition on use a good volt meter and there should be around 5v on the red white and 0.5v max on the brown/white (ecu earth track?) double check by checking the voltage across the 2 terminals and it should read around 5v! if all ok turn off ignition and remove the tw sensor with a 19mm deep socket and ratchet, Snap On work quite well for me (skinning obligatory knuckles in the process). now with an accurate ohm meter, mines an AVO multi meter, check the resistance across the 2 pins and you should get around 12 k ohms cold (as far as I can ascertain) dropping to about 0.15 k ohms at about 90 deg c, now these values didn't concern me too much as what I was looking for basically was a good measurable difference between hot and cold. the values on mine were 0.015 k ohms cold and 0.015 k ohms hot, now this is what I was looking for and the conclusion is the tw sensor is goosed!
Now all I have to do is find a tw sensor that has the right signal range and fits in the hole and the plug, fit it, plug it in wipe up the pink puddle under the car, remember to put a tray under if I have to do it again, kill the ecu codes then try it, then put clean plasters on knuckles. open bottle of beer and relax knowing you have saved yourself a fortune. Simples

[Steve_M]

TW sensor is the 2 pin connector on the water elbow under the distributor. ( single pin sensor is gauge)

Red/White and Brown/Black wires.

With connector disconnected, Brown/Black should be ground and Red/White is Approx 5 volts with IGN on. (check across the connector) If not OK check Red/White with known good ground to check voltage and check ground with known good 12 volt.

Sensor should be between 200 to 400 ohms engine at normal operating temperature. (I measured 1500 ohm on a sensor I have here at ambient temp 22 C)

Part number for sensor is 37870-PK2-005 - £68.25 for a genuine sensor with stock in Europe.

37870-PJ7-003 is an alternate part number from differant supplier.

Sensor is quite a common Honda part, fits civic, Accord, CRX, S2000, NSX

A Quick search came up with these sites, for a non genuine part:

http://www.ignitioncarparts.co.uk/PartDetails.aspx?s_pc=ICP-WTS3198&s_vid=

or

http://www.auto-essentials.co.uk/ecomm/catalog/temperature-sensor-honda-rover-mek100070-37870pj7003-vct110-p-3388.html

[obiwanwasabe]

Thanks Steve, thats the part I reckoned it was. Other recommendation it Calendula and Hypericum cream for skinned knuckles!

[obiwanwasabe]

All done, car running fine again now, Idle needed readjusting, dunno where I got those ohmic values from but they were wrong, Steve_M 's values were correct. fitted the motquip sensor, total cost £9.98 for sensor, £3.00 for 1 ltr engine coolant, £3.50 for antiseptic cream for knuckles.

[gymm]

Very glad the Beat and your knuckles are sorted! Wouldn't be the same without a few 'battle scars' but all forgotten once you go for a drive! :)

[fxdlidon]

Just had the same problem on mine. It's really simple to do if you lift out the distributer first. No Check Engine light now and the car is running sweetly :)