2005 Honda Accord - Coolant Sensor Reversed?

[HINEMANS]

This is driving me crazy; car came in with P2183 and P2185 coolant temp sensor 2 codes.

I hooked up the scan tool and the sensor read 455 degrees. Checking the wiring, I had 5v reference and crossing terminals the temp drops to -40. So we ordered a sensor from the dealer part# (37870-raa-a01) after putting in the sensor on a cold engine, the temp read 255 degrees and as the engine warms up it dropped to 30 degrees when cooling the sensor down the temp came back up. we asked the dealer to double-check the part # to the vehicle and they said it was right. they even sold the car new to the owner, so we tried another sensor from the dealer to eliminate a bad part but have the same problem. Any ideas? This should be an easy fix.

[steven kiser]

i've seen occasions like this where someone pulled the wires out of the connector and installed them incorrectly. does the coolant fan work?

[HINEMANS]

terminals are in the correct position according to mitchell and yes the cooling fan does work.

[wbuxton]

I'm assuming this is a 3 wire sensor?

[Pauls Automotive]

I would do a voltage drop test on all wires and verify wires is good all the way back to computer as well as verify voltage outputs and grounds. If all checks good then unlikely as it may sound the computer is probably bad.

[HINEMANS]

its a two wire connector and the sensor is located at the lower left of the radiator i,ve checked the wires to the computer and the output voltages through the scantool and it al seems to be fine.

[Pauls Automotive]

I wouldn't trust what the scanner is interurpting. I would go directly to the source and check it with a DVOM. I've been burned before by a scanner.

I just checked my repair program. There are two coolant sensors on this vehicle. One in the radiator and one at the right rear of the cylinder head. Make sure you aren't checking the good one. It may be the other that is at issue.

[Tim Martin]

This must be a four cylinder engine. If I recall correctly there are 2 sensors on the radiator. Are you sure you replaced the right one? The one is a radiator cooling fan switch and the other is a coolant temp sensor. 2 different sensors. Have seen some techs get this mixed up, and of course the parts guy will sell you what you ask for. Just a thought about the 2 sensors.

[HINEMANS]

the sensor i'm checking on the radiator is the bad one it resistance tests at 64k ohms the new sensor starts out at about 2200 ohms the sensor on the motor is checking fine also when looking through the scan tool the bad reading changes when i unplug or jumper the terminals on the sensor on the radiator i also double checked and there is only one sensor on the radiator every thing seems fine but the actual new sensor is changing resistance the wrong way. sending the computer temp down as the engine warms up and temp up when the engine cools. do i have an odd ball that needs a diff type of sensor or what it worked fine until the sensor went south and now i feel i can't find a proper replacment part and i,m using dealer parts

[Tim Martin]

my guess is you may be getting the wrong sensor.

[HINEMANS]

it's off to the dealer i'll let you all know what it is if i find out from the customer.

[steven kiser]

in the future make sure the plastic head of the sensor is the same color of the obe you're replacing. in some instances i'll request a parts diagram from the dealer and check on tsb's. i have (rarely) ran into situations that a sensor has been updated and the pcm needs to be reprogramed

[HINEMANS]

i went that round with the dealer asking if the color should be the same because the old one is black and the new one is white we also called another dealer for a second opinion they both say its the only option. i also talked to one of the techs at the honda dealer and he had no advice although i felt like i was getting the run around.

[brianp87]

90% of the time you will know more then the dealership. There techs are typically not well versed and not nearly as qualified or skilled as us.

[wbuxton]

90% of the time you will know more then the dealership. There techs are typically not well versed and not nearly as qualified or skilled as us.

Can we gt an AMEN!

They typically only know how to replace 1 part that failed. And they get paid if they guess wrong

[steven kiser]

is there any history on this car? was it involved in an accident or is the harness looking out of whack.i've seen more that one time where a harness has been routed wrong and pluhs are plugged into incorrect sensors. a harness that's routed incorrectly is usually easy to spot. the color of the plug may match the sensor color. take a look at the harness and see if there are any other miss matched combo's. oh ya, unless you have a good strong relationship with a tech at a dealer don't expect any help. a good in is asking your snappy or mac or matco driver if he knows of any friendly dealer techs that will help. that's worked for me. on occasion if i get help with a real head bangr this way i'll reward both buy getting that tech a gift card through the tool truck for $25. the tech gets rewarded with the certificate and the driver with a purchase. i get rewarded with the fix and another relationship with a dealer tech. everyone makes out.

[AutoworksTodd]

How about putting both sensors in water and heating it up while monitoring both sensors, and see what they do? What about checking the year before or the year after to see if they list a different part??? Did you monitor the old one in the car to see what it read, cold to hot??

[HINEMANS]

customer took car to the dealer and they claim to have just replaced the sensor when the customer returnd to our shop for regular maintenance i checked and the sensor was new but it was responding properly when i looked at the pids in the computer. guess we'll never know the answer.

[steven kiser]

just for s&g's see if the cooling fan relay has been replaced when you get a chance.