My RX 300 with ran about 30 miles this morning, we had heavy rain today, in the PM I cranked it up, it ran at very low idle speed and then died off, I tried it couple of times and engine starts as if its half dead & the check engine light came on. I neved had this error code before, adn the RX was runnig ngreat so far.

I used a OBD II scanner and I got the error code P0115 - Engine coolant temp circuit malfunction.


It's still raining adn I did not pop the hood up.

How do I fix this. I tried to search the forums but have no luck in finding anything usefull to me, or I was unsuccessfull in searching.

Can anyone point me to the thread if this topic was discussed & resolved before, or suggest some tips to get this thing to work.

Thanks.

 

Found this info on the net.

P0115 - Engine Coolant Temperature Circuit Malfunction
OBD-II Trouble Code Technical Description

Engine Coolant
Temperature Circuit Malfunction
What does that mean?

The ECT (Engine coolant temperature) sensor is basically a thermistor that changes resistance with temperature. Usually a two wire sensor, a 5Volt reference from PCM (Powertrain Control Module) and ground signal to PCM. This is different from a temperature SENDER (which usually operates the dash temperature gauge and operates in a similar way as the SENSOR, only it's a different circuit than what a P0115 is referring to). As the temperature of the coolant changes, the resistance changes on the ground signal to the PCM. When the engine is cold, the resistance is high. When the engine is warm, the resistance is low. If the PCM detects a voltage condition that seems abnormally low or high, P0115 will set.

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Symptoms

Symptoms of a P0115 DTC code may include:

* MIL (Malfunction Indicator Lamp) illumination will always occur
* Vehicle may be hard to start
* May blow a lot of black smoke and run extremely rich
* Engine may want to die or backfire in tailpipe
* Engine may run lean and increased Nox emissions may be apparent (Requires gas analyzer)
* Cooling fans may run all the time when they shouldn't be, or not at all when they should be

Causes

Usually the cause can be traced to a bad ECT sensor, however that doesn't preclude the following:

* Wiring or connector damaged at sensor
* Open or short in reference or signal circuit
* Open or short in signal circuit
* Bad PCM

Possible Solutions

First, visually check the sensor for damage to wiring or connector and repair as necessary. Then, if you have access to a scanner, determine what the temperature of the engine is. (If you don't have access to a scan tool, using the dash temperature gauge may not be an effective way to determine coolant temperature. This is because the P0115 code is referring to the ECT SENSOR, and the dash gauge is operated by, usually a one-wire SENDER. Basically a different sensor that the code doesn't refer to.)

2. If the engine temperature is abnormally high, around 280 deg. F, that's abnormal. Unplug the sensor on the engine and see if the signal drops to, say, negative 50 deg. F. If it does, then it's a good bet the sensor is bad, internally shorted, causing a low resistance signal to be sent to the PCM. However if you want to be sure it's the sensor and not the wiring, there's a couple tests you can do. With the ECT sensor unplugged, check that you have 5 volts on the reference circuit with KOEO (Key on engine off). Also you can check the resistance of the sensor to ground using an Ohm meter. The resistance of a normal sensor to ground will vary a little depending on the vehicle, but basically, if the temp of the engine is around 200 deg. F., the resistance will be about 200 Ohms. If the temperature is about 0 def. F., the resistance will be over 10,000 Ohms. With this test you should be able to tell if the resistance of the sensor matches the temperature of the engine. If it's not accurate according to your engine's temperature, then you probably have a bad sensor.

3. Now, if the temperature of the engine according to the scanner is around 280 deg. F. and unplugging the sensor doesn't cause the reading to drop to negative 50 deg. F, but it stays at the same high temperature reading, then you'll need to repair the short on the signal circuit(ground) to the PCM. It's shorted directly to ground somewhere.

4. If your temperature reading of the engine according to the scanner is showing negative 50 deg. F or so, (and you don't live in the arctic!) unplug the sensor and check for a 5V reference present at the sensor.

5. If there isn't, then check at the PCM connector for proper 5V reference. If it's present at the PCM connector, then repair the open or short on 5V reference from PCM. If there is no 5V reference present at the PCM connector, then you're done with your diagnosis and you may have a PCM fault. 6. If the 5V reference circuit is intact, then check the ground signal to the PCM using the previous ground resistance test. If the resistance isn't normal for the temperature of the engine, then ohm the resistance of the ground signal to the PCM by removing the ground signal wire from the PCM connector. The wire should have no resistance, unplugged from the PCM to the sensor. If it does, repair open in the signal to the PCM. If it doesn't have any resistance on the ground signal wire and the resistance test of the sensor is normal, then suspect a faulty PCM.

Other coolant engine light codes: P0115, P0116, P0117, P0118, P0119, P0125, P0128
Related P0115 Forum Topics

* What these codes mean P0135, P0325 and P0115.
* 96 nissan maxima codes p0115 p0125
* 97 F150 4.6 Codes P1151, P0115, P0141, P0155
* Go to the auto repair forum now to ask your question!

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The wires have been cut by roddent, they tried to make a nest with grass. The wires have been cut right at the point where it exits the harness and then again at the point where it connects to the connector.


Do I have to get the entire harness to fix thsi, if I solder the wire, wll it hold?

 

You can try soldering it...was very common to see mechanics to do this in Mexico where we had an abundant rat problem.

 

Making a wire connection is easy, but to do it right takes patience ans skill. The problem with bad joints shows up over time (not on the day of repair)

1st you must ensure that you are not making the harness any shorter. So if things are destroyed then you must add a piece of wire. [so if no cooper is lost when you splice you are making the wire 1.5" shorter]

2nd Every effort should be made that the joints are not lined up. It is better to make staggered connections. [if more than one wire is cut]

3rd Make sure you slide shrink tubing over wire before making a solder joint.

4th you should bare about 3/4" of copper and and the wires should be aligned facing each other with copper overlapping each other.

5th Take a single strand of copper and wind it over the overlaps (perpendicular to the overlap copper). The winding should be done evenly and not overlap on its self (for neatness). Snip ends and make sure you squeeze the ends down as they might puncture the shrink tubing.

6h Now is the time to solder & keep it away from the insulation. [mid 1/2"] is good. [Use the right soldering iron for automotive wires 25watt is good.

7th. The soldered joint will still be less thicker than the wire with insulation.

8th. Slide the shrink tubing over the joint and use heat gun to shrink it.

9th. Make sure the wire/harness is held by rigid support as the joint(s) should not be subjected to vibration or tension.



Salim

 

Thanks very much, I soldered it, so far its good.

I put moth ***** in that area, to keep this rodent our; it smells bad, at least the car is drivable.

I ordered this solution from "Rataway.com"that can be sprayed on the wires in the engine compartment.

The reviews seems to indicate that this products helps to keep the rodents out of the engine compartment even if the wires or wire protectors are made of soy based products.


Thanks again for all the fast responses.