"Eric" <ewong1@motorola.com> wrote in
news:ffo8sh$9c6$1@newshost.mot.com:

> I have a 1991 Honda Accord EX with 470000 miles. Lately, I exchanged
> the thermostat and code error 6 popping up. Refer to the service
> manual, it is coolant temperature sensor. I followed the service
> manual and measure the resistance on the sensor when engine warm up
> with cooling fan on. It is open compare to spec with few hundreds ohm



I don't know what kind of manual you're using, but it's wrong.

The resistance should be checked with the ignition OFF and the connector
UNPLUGGED. You check the resistance between the pins of the sensor itself.

You should check resistance both engine hot and engine cold.

Full-hot, you're looking for about 200-400 ohms. Cold, the resistance
should be about 10,000-20,000 ohms.



> and I determined that it is the sensor problem. But when I try to
> measure the voltage on the sensor connector and I notice it is 12V
> instead of 5V mention on the manual. After that, I measured another
> good same year and model vehicle from my friend and it is 12V output
> on the sensor connector and the sensor is open when engine hot.



To check the voltage, you turn the ignition to "II" (engine can be any
temperature), unplug the connector from the sensor then probe for voltage
between the two wires in the connector.

Do all the checking procedures correctly and see what you get.




--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/