Hello all, I've been the proud owner of a shiny blue TSX since 2006.
I've just had my first check engine light come and it said Check emission system. I took it to the dealer and they said the ECT sensor and IAT sensor would need to be replaced and quoted me $646.11.
I'd like to try and do this repair myself, but the problem is I don't know what either of these two sensors look like or where they are. Could someone post a picture or instructions on where to find them? And where would be a good place to find replacements for these sensors?

 

The IAT is on the intake tube and costs ~$27 onine.

#14 in the diagram
http://www.acuraautomotiveparts.org/...4sea01_b01.png

The ECT is on the bottom of the radiator and about ~$26.

#9 in the diagram
http://www.acuraautomotiveparts.org/...4sea01_b05.png

They are easy to replace. However, I would reset the codes first and verify which one is causing a problem, as those two sensors are not directly related, unless there's a problem with the common ground connection.

 

The exact errors Acura said the car was giving were P0128, P2185 and P0111. And they said it was one of those two sensors was not communicating with each other properly anymore. The car has been running 100% so far I haven't noticed and changes in running temperature or anything weird with the idle.

 

Isn't the sensor on the bottom of the radiator (#9) associated with P2185 (p/n 37870-RAA-A01, Panasonic) and the ECT associated with P0128 is p/n 37870-PNA-03, Keihin located in the engine block close to the WP?

 

OK:

P0111 "Intake Air Temperature (IAT) Sensor Circuit Range/Performance Problem"

P0128 "Cooling System Malfunction"

P2185 "Engine Coolant Temperature (ECT) Sensor 2 Circuit High Voltage"

So, P2185 likely caused the P0128, as one of the checks for it is the function of ECT #2. Trouble shooting ECT is looking to isolate loose wire then replace sensor if one isn't loose. IAT is straight replace it.

My .02, other than draining coolant, the swaps are simple and the prices are not too high...you take a chance and do it yourself and save 550 or so, but maybe not solve the problem. The dealer should discount the repair by the diagnostic cost, so the actual repair is less than quoted, but at least it should be solved. It's a toss-up.

 

DD, thanks for your response here and on my other related thread. In my case, since I only have P0128, can I rule out a problem with ECT 2?

 

No, the ECT 2 sensor is a possible issue for a P0128...

Back to trouble shooting, assuming a 2007:

First check is radiator fan function...second is thermostat...third is ECU/PCM reflash...then connection check on ECT 1 & 2...failing all that, replace ECU/PCM.

Proper trouble shooting requires a HDS computer to ensure certain messages occur before the next step...sorry.

 

Yep, you are 100% correct about needing the HDS tool to properly trouble shoot. OTOH, the cost of the thermostat is not much and she needs a coolant drain/fill anyway. So, I will check the ECT2 pins for corrosion (I saw the Honda S/B on this which says corroded ECT2 pins can throw P0128), check the fan operation and then replace thermostat.

Is there someway I can tell if the ECU needs to be reflashed? That is, if I call American Honda with the VIN, can they tell me? Thanks.

 

The reflash is for updates, so Honda/Acura should be able to tell if your car is current as they log the services.

 

I'm dealing with the same issue on my 06 TSX. I picked up the only sensor that Autozone carries and notice the upper and lower ECT are very similar. In the Shop manual, the lower sensor that bolts to the radiator doesn't appear to have a nipple the goes into the rat but the upper ECT does have the nipple. The duralast part # is SU5584. I know the OEM part#'s are slightly different. I don't want to drain and pull the lower sensor and it not be the correct one.

 

Here's some pics of the Autozone part and the terminals on my sensor in the radiator.http://imageshack.com/a/img706/7332/4rox.jpg
http://imageshack.com/a/img854/1346/pzwv.jpg
http://imageshack.com/a/img59/529/enm8.jpg

 

http://imageshack.com/a/img706/7332/4rox.jpg

 

 

I returned the Duralast sensor as when I checked it with my meter the reading was closer to the ECT-1. Purchased the ECT-2 from OEMAcuraparts.com and installed it this weekend. Only took about 5 minutes to pull the sensor and replace. Torqued to specs and refilled the radiator. Draining the system took about 15-20 minutes. Drove the car for two cycles and it cleared the code on it's own. The terminals on my sensor were fine but the ohm reading was only about 45 ohms.