Lincoln P0478 Exhaust Pressure Control Valve High

Description

OBD-II Trouble Code Description for P0478 Lincoln

Exhaust Pressure Control Valve High

What does this mean?

OBD2 Code P0478 Lincoln definition:
Exhaust Back Pressure Regulator – Is a variable position valve that controls exhaust back pressure during cold ambient temperatures to increase cab heat and decrease the amount of time needed to defrost the windshield. The PCM uses the measured exhaust back pressure, (ambient) intake air temperature, engine oil temperature and engine load to determine the desired exhaust back pressure. Valve position is controlled by switching the output signal circuit to 12 volts inside the PCM. On/off time is modulated from 0 to 99 % dependent upon the exhaust back pressure desired. Upon each initial engine start-up, the PCM exercises the exhaust back pressure valve by commanding it to cycle on and off once. If upon start-up the temperature of intake air sensed by the IAT sensor is < 37¡ãF (5¡ãC) and the oil temperature sensed by the EOT sensor is between 32¡ã-140¡ãF (0-60¡ãC) it will continue to keep the back pressure valve partially closed. As the oil temperature rises during engine operation, the PCM will control the valve in response to the rising oil temperature.

Symptoms

Possible sumptoms of OBD code P0478 Lincoln
– Engine Light ON (or Service Engine Soon Warning Light)

Causes

Possible causes of OBD code P0478 Lincoln
– Exhaust Back Pressure Valve The Error code is generally activated on detection of the following conditions: An open or shorted to ground control circuit can be detected by an on demand output circuit check performed during the engine off test. Problems with either the Exhaust Back Pressure Device or the tube between the exhaust manifold and the EBP sensor can be detected during the exhaust back pressure step test, in which the PCM commands and then measures a specific preprogrammed pressure and then measures time for pressure decay during the engine running test. If the PCM detects an EBP, EOT or IAT sensor fault it will disable the exhaust back pressure regulator.

Possible Solutions

Check the Exhaust Back Pressure Valve (EBPV) butterfly valve is opening and closing freely and not sticking. If it seems to move freely you can then check the connector and circuit for the EBPV solenoid.


The OBD2 Code Information Be Applicable For Lincoln:

2013 Lincoln MKZ,2013 Lincoln MKT,2013 Lincoln MKS,2013 Lincoln MKC,2012 Lincoln MKZ,2011 Lincoln MKX,2010 Lincoln MKZ,2010 Lincoln MKT,2009 Lincoln MKS,2009 Lincoln C Concept,2008 Lincoln MKT Concept,2007 Lincoln Navigator,2007 Lincoln MKZ,2007 Lincoln MKX,2007 Lincoln MKR Concept,2006 Lincoln Zephyr,2006 Lincoln Mark LT,2006 Lincoln MKS Concept,2004 Lincoln Mark X Concept,2004 Lincoln Aviator Concept,2003 Lincoln Town Car,2003 Lincoln Aviator,2001 Lincoln MK9

 

Note:

1. The list of automotive Makes at the right edge of the screen. The currently selected ODB-ii codes is for the Lincoln makes.

2. Look up the other OBD II Trouble Codes, please use the search box. Enter the 5 character trouble codes in the search box and submit the search.

3. Don’t assume a particular OBD-II code means the same for other auto manufacturers as there are many makes specific codes in use.

4. If your OBD-II trouble codes are for a different car, select that vehicle series before searching for the diagnostic codes because not all OBD2 codes used by one manufacture are used by the other makes.

5. The information contained on this site is presented for informational purposes only. We are not responsible for any actions you take on your vehicle. If you have any doubt as to repairs on your vehicle, please contact your technician.