BMW P0115 Engine Coolant Temperature Sensor Performance

Description

OBD-II Trouble Code Description for P0115 BMW

Engine Coolant Temperature Circuit

What does this mean?

OBD2 Code P0115 BMW definition:
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 BMW 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 BMW will set.

Symptoms

Possible sumptoms of OBD code P0115 BMW
Symptoms of a P0115 BMW 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

Possible causes of OBD code P0115 BMW
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 BMW 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.


The OBD2 Code Information Be Applicable For BMW:

2013 BMW X6 M50d,2013 BMW X6,2013 BMW X5 eDrive Concept,2013 BMW X5 Security Plus Concept,2013 BMW X5 M50d,2013 BMW X4 Concept,2013 BMW X1,2013 BMW Pininfarina Gran Lusso Coupe,2013 BMW M6 Coupe US-Version,2013 BMW M6 Coupe,2013 BMW M6 Convertible,2013 BMW M5 US-Version,2013 BMW M550d xDrive Touring,2013 BMW M550d xDrive,2013 BMW M4 Coupe Concept,2013 BMW M135i,2013 BMW Active Tourer Outdoor Concept,2013 BMW 7 ActiveHybrid,2013 BMW 750Li,2013 BMW 7-Series,2013 BMW 640i Gran Coupe,2013 BMW 640d xDrive Coupe,2013 BMW 6-Series Gran Coupe UK Version,2013 BMW 6-Series Gran Coupe,2013 BMW 5 ActiveHybrid,2013 BMW 4-Series Coupe Concept,2013 BMW 3 ActiveHybrid,2013 BMW 3-Series Touring,2013 BMW 3-Series Long Wheelbase,2013 BMW 1-Series 3-door,2012 BMW i8 Spyder Concept,2012 BMW i3 Coupe Concept,2012 BMW Zagato Roadster Concept,2012 BMW Zagato Coupe Concept,2012 BMW M5 UK Version,2012 BMW M5,2012 BMW M3 DTM Champion Edition,2012 BMW M3 CRT,2012 BMW M135i Concept,2012 BMW Active Tourer Concept,2012 BMW 650i Convertible,2012 BMW 640d Coupe,2012 BMW 6-Series Coupe,2012 BMW 6-Series Convertible,2012 BMW 3-Series,2012 BMW 1-Series Urban Line,2012 BMW 1-Series Sport Line,2012 BMW 1-Series Coupe,2012 BMW 1-Series Convertible,2012 BMW 1-Series,2011 BMW i8 Concept,2011 BMW i3 Concept,2011 BMW Z4,2011 BMW X5,2011 BMW X3 xDrive35i,2011 BMW X3 xDrive20d,2011 BMW X3,2011 BMW X1 xDrive28i,2011 BMW M5 Concept,2011 BMW M3 Pickup Concept,2011 BMW M3 GTS,2011 BMW M3 Frozen Gray,2011 BMW ConnectedDrive Concept,2011 BMW ActiveE Concept,2011 BMW 750Li,2011 BMW 5-Series Touring,2011 BMW 5-Series Long-Wheelbase,2011 BMW 5-Series,2011 BMW 335is Coupe,2011 BMW 328 Hommage Concept,2011 BMW 3-Series Coupe,2011 BMW 3-Series Convertible,2011 BMW 1-Series M Coupe US Version,2011 BMW 1-Series M Coupe UK Version,2011 BMW 1-Series M Coupe MotoGP Safety Car,2011 BMW 1-Series M Coupe,2010 BMW Z4 UK Version,2010 BMW Z4 GT3,2010 BMW Z4,2010 BMW X6 M,2010 BMW X6 ActiveHybrid,2010 BMW X5 M,2010 BMW X1,2010 BMW Scooter C Concept,2010 BMW M3,2010 BMW Gran Coupe Concept,2010 BMW ActiveE Concept,2010 BMW 7 ActiveHybrid,2010 BMW 760Li,2010 BMW 7-Series High Security,2010 BMW 6-Series Coupe Concept,2010 BMW 5-Series Gran Turismo,2010 BMW 5-Series ActiveHybrid Concept,2010 BMW 320d EfficientDynamics,2010 BMW 135i Coupe,2010 BMW 135i Convertible,2009 BMW X6 UK Version,2009 BMW X6,2009 BMW X5 xDrive35d BluePerformance,2009 BMW X5 Security Plus,2009 BMW X5 Security,2009 BMW X3 Limited Sport Edition,2009 BMW M3 Saloon UK Version,2009 BMW M3 Race Version,2009 BMW M3 Convertible UK Version,2009 BMW M3 Convertible,2009 BMW EfficientDynamics Concept,2009 BMW 750Li,2009 BMW 730d,2009 BMW 7-Series UK Version,2009 BMW 7-Series,2009 BMW 5-Series Gran Turismo Concept,2009 BMW 335d BluePerformance,2009 BMW 3-Series UK Version,2009 BMW 3-Series Touring UK Version,2009 BMW 3-Series Touring,2009 BMW 3-Series,2009 BMW 1-Series Convertible UK Version,2008 BMW X5 M-Package,2008 BMW X1 Concept,2008 BMW M5 Touring,2008 BMW M3 Sedan US-Version,2008 BMW M3 Sedan,2008 BMW M3 Coupe US-Version,2008 BMW M3 Coupe UK Version,2008 BMW M3 Coupe,2008 BMW M1 Concept,2008 BMW M-Zero Concept,2008 BMW GINA Light Visionary Model Concept,2008 BMW EfficientDynamics Concept,2008 BMW Coupe Range,2008 BMW 7-Series ActiveHybrid Concept,2008 BMW 650i Convertible,2008 BMW 635d Coupe,2008 BMW 530i,2008 BMW 5-Series Touring,2008 BMW 5-Series Security,2008 BMW 5-Series,2008 BMW 135i Coupe,2008 BMW 128i Convertible,2008 BMW 1-Series Range,2008 BMW 1-Series Coupe,2008 BMW 1-Series Cabrio,2008 BMW 1-Series 5-door,2008 BMW 1-Series 3-door,2007 BMW X6 Concept,2007 BMW X6 ActiveHybrid Concept,2007 BMW X5 4.8i,2007 BMW X5 3.0d,2007 BMW X3,2007 BMW M6 Convertible Neiman Marcus,2007 BMW M6 Cabrio,2007 BMW M5,2007 BMW M3 Concept,2007 BMW Hydrogen 7,2007 BMW Concept CS,2007 BMW 530Li,2007 BMW 335i Coupe,2007 BMW 335i Convertible,2007 BMW 1-Series tii Concept,2006 BMW Z4 Roadster,2006 BMW Z4 M Roadster,2006 BMW Z4 M Coupe UK version,2006 BMW Z4 M Coupe,2006 BMW Z4 Coupe,2006 BMW Mille Miglia Coupe Concept,2006 BMW Art Car Collection,2006 BMW 7 Series High Security,2006 BMW 760Li,2006 BMW 750i,2006 BMW 750Li with Shadow Line,2006 BMW 750Li,2006 BMW 330i,2006 BMW 325i Touring,2006 BMW 320si E90 WTCC,2006 BMW 320si,2006 BMW 320d Touring,2006 BMW 320d,2005 BMW Z4 Coupe Concept,2005 BMW X5,2005 BMW X3 EfficientDynamics Concept,2005 BMW X3,2005 BMW M6,2005 BMW M5,2005 BMW H2R,2005 BMW 630i,2005 BMW 545i Touring,2005 BMW 530xi Touring,2005 BMW 530xi,2005 BMW 530d Touring,2005 BMW 330i M-Package,2005 BMW 320d Touring,2005 BMW 130i M-Package,2005 BMW 130i,2005 BMW 120i UK Version,2005 BMW 120i,2005 BMW 120d,2004 BMW X5 4.8is,2004 BMW X5 4.4i,2004 BMW X3 3.0i,2004 BMW X3 2.0d,2004 BMW H2R Hydrogen Racecar,2004 BMW Concept M5,2004 BMW 645Ci Convertible,2004 BMW 645Ci,2004 BMW 5 Series,2004 BMW 530i,2004 BMW 530d,2004 BMW 330Ci Coupe,2004 BMW 330Ci Convertible,2004 BMW 330Cd Coupe,2004 BMW 325Ci Coupe,2004 BMW 320Cd Convertible,2004 BMW 318Ci Convertible,2003 BMW Z4 2.5i,2003 BMW Z4,2003 BMW M3 CSL,2003 BMW 760Li E66,2003 BMW 325ti Compact,2003 BMW 3-Series Compact,2002 BMW xActivity Concept,2002 BMW X5 4.6is,2002 BMW CS1 Concept,2002 BMW 7 Series,2002 BMW 760i,2002 BMW 760Li Yachtline Concept,2002 BMW 740d,2002 BMW 730d,2002 BMW 3-Series Touring,2002 BMW 3-Series,2001 BMW Z8

 

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