Fiat P0405 Exhaust Gas Recirculation Position Sensor Circuit Low Voltage

Description

OBD-II Trouble Code Description for P0405 Fiat

Exhaust Gas Recirculation Sensor “A” Circuit Low

What does this mean?

OBD2 Code P0405 Fiat definition:
There are different designs of EGR (Exhaust Gas Recirculation) systems, but they all operate in a similar way. The EGR valve is a PCM (Powertrain Control Module) controlled valve that allows measured amounts of exhaust gasses to pass back into the cylinders to be burned with the air/fuel mixture. Since exhaust gas is an inert gas that displaces oxygen, injecting it back into the cylinder can lower combustion temperatures which helps to improve NOx (oxides of nitrogen) emissions. EGR isn’t needed on cold startup or at idle. EGR is commanded on under certain conditions like startup or at idle. EGR is commanded on under certain conditions like partial throttle or decel depending on engine temperature and load, etc. Exhaust gasses are supplied to the EGR valve from an exhaust pipe or the EGR valve may be mounted directly in the exhaust manifold. When needed, the valve is commanded “on” allowing the gasses to pass into the cylinders. Some systems divert exhaust gasses directly into the cylinders while others simply inject it into the intake manifold where it is then pulled into the cylinders. while others simply inject it into the intake manifold where it is then pulled into the cylinders.

Some EGR systems are quite simple while others are a little more complicated. Electrically controlled EGR valves are directly controlled by the PCM. A wiring harness plugs into the valve itself and is commanded by the PCM as it sees the need. These can be 4 or 5 wire. Usually 1 or 2 grounds 12 volt ignition feed, a 5 volt reference circuit, and a feedback circuit. Other systems are vacuum controlled. These are quite simple. The PCM controls a vacuum solenoid which when activated, allows vacuum to travel to the EGR valve and open it. There should also be an electrical connector on this type of EGR valve for the feedback circuit. The EGR system feedback circuit allows the PCM to see if the EGR valve pintle is actually moving as it should. If the feedback circuit detects that the voltage is unusually low, or it’s position is lower than it’s commanded to be, P0405 Fiat may set.

Symptoms

Possible sumptoms of OBD code P0405 Fiat
MIL (Malfunction Indicator Lamp) illumination

Causes

Possible causes of OBD code P0405 Fiat
Short to ground in EGR signal or Reference circuits
Short to voltage in EGR ground or signal circuits
Bad EGR valve
Bad PCM wiring issues due to chafing or loose terminals

Possible Solutions

If you have access to a scan tool you can command the EGR valve on. If it responds and the feedback indicates the valve is moving properly then the problem may be intermittent. Sometimes in cold weather, moisture can freeze in the valve causing it to stick. After the vehicle warms up the problem may disappear. Carbon or other debris can lodge in a valve causing it to stick also
If the EGR valve doesn’t respond to your commands with the scan tool, disconnect the EGR harness connector. Turn the key to on position, engine off (KOEO). Using a voltmeter, check for 5 volts on the reference wire to the EGR valve. If there is no 5 volts, is there any voltage at all? If there is 12 volts, then repair short to voltage in the 5 volt reference circuit. If there is no voltage connect a test light to battery voltage and probe the 5 volt reference wire. If the test light illuminates, the 5 volt reference circuit is shorted to ground. Repair as necessary. If the test light doesn’t illuminate check for an open in the 5 volt reference circuit. Repair as necessary
If there is no apparent problem and there is no 5 volt reference, PCM may be at fault, however other codes will likely be present. If 5 volts are present on the reference circuit, jumper the 5 volts to the EGR signal circuit. Now the EGR position on the scan tool should read 100 percent. If it doesn’t connect test light to battery voltage and probe the EGR signal circuit. If it illuminates, then the signal circuit is shorted to ground. Repair as necessary. If the light doesn’t illuminate, check for an open on the EGR signal circuit. Repair as necessary.
If, after jumpering the 5 volt reference circuit to the EGR signal circuit the scan tool EGR position reads 100 percent, then check for poor terminal tension at the EGR valve connector. If the wiring is okay, replace the EGR valve.

Related Codes

P0401 Fiat P0402 Fiat P0403 Fiat P0404 Fiat P0406 Fiat P0407 Fiat P0408 Fiat P0409 Fiat


The OBD2 Code Information Be Applicable For Fiat:

2013 Fiat Viaggio,2013 Fiat Strada,2013 Fiat Panda UK Version,2013 Fiat Panda Trekking,2013 Fiat Panda 4×4,2013 Fiat Panda,2013 Fiat 500S,2013 Fiat 500L,2013 Fiat 500C Abarth,2012 Fiat Punto,2012 Fiat Palio,2012 Fiat Freemont AWD,2012 Fiat Freemont,2012 Fiat 695 Abarth Maserati Edition,2012 Fiat 500 Abarth,2011 Fiat Uno,2011 Fiat Punto Evo Abarth esseesse,2011 Fiat Punto Evo Abarth,2011 Fiat Idea,2011 Fiat Bravo,2011 Fiat 500 Sport,2011 Fiat 500 Coupe Zagato Concept,2011 Fiat 500C Abarth esseesse,2011 Fiat 500C Abarth,2010 Fiat Uno Cabrio Concept,2010 Fiat Sedici,2010 Fiat Punto Evo,2010 Fiat Doblo Cargo,2010 Fiat Doblo,2010 Fiat 500 Abarth R3T,2010 Fiat 500C,2009 Fiat Grande Punto Natural Power,2009 Fiat Fiorino Qubo,2009 Fiat 695 Abarth Tributo Ferrari,2009 Fiat 500 Barbie Concept,2009 Fiat 500 Abarth esseesse,2009 Fiat 500 Abarth Assetto Corse,2009 Fiat 500 Abarth,2008 Fiat Portofino Concept,2008 Fiat Panda Cross,2008 Fiat Grande Punto Abarth,2008 Fiat Grande Punto,2008 Fiat Fiorino,2008 Fiat Croma,2008 Fiat Bravo 1.6 Multijet 16v,2008 Fiat 500,2007 Fiat Panda 100HP,2007 Fiat Linea,2007 Fiat Grande Punto Abarth S2000,2007 Fiat Grande Punto Abarth Preview,2007 Fiat Bravo,2006 Fiat Ulysse,2006 Fiat Sedici,2006 Fiat Panda Multi Eco Concept,2006 Fiat Panda Cross,2005 Fiat Panda Alessi,2005 Fiat Panda 4×4 1.3 Multijet,2005 Fiat Oltre Concept,2005 Fiat Idea,2005 Fiat Grande Punto,2005 Fiat Doblo Cargo,2005 Fiat Doblo,2005 Fiat Croma,2005 Fiat 600 50th,2004 Fiat Trepiuno Concept,2004 Fiat Strada Malibu,2004 Fiat Stilo M.Y. 1.9 Multijet 5door,2004 Fiat Seicento,2004 Fiat Punto Rally,2004 Fiat Panda 4×4,2004 Fiat Multipla,2004 Fiat Idea 5terre Concept,2003 Fiat Strada,2003 Fiat Punto Sporting,2003 Fiat Punto Rally,2003 Fiat Punto Natural Power,2003 Fiat Punto Dynamic,2003 Fiat Punto Active,2003 Fiat Panda Emotion,2003 Fiat Panda Dynamic,2003 Fiat Panda Actual,2003 Fiat Panda,2003 Fiat Marrakech Concept,2003 Fiat Idea 1.9 Multijet Dynamic,2003 Fiat Idea 1.4 16v Emotion,2003 Fiat Idea,2003 Fiat Barchetta First Class of Alviero Martini,2003 Fiat Barchetta,2002 Fiat Ulysse Emotion 2.0 16v,2002 Fiat Ulysse 2.0 JTD,2002 Fiat Ulysse,2002 Fiat Stilo Multi Wagon Dynamic,2002 Fiat Stilo Multi Wagon Actual,2002 Fiat Stilo Multi Wagon,2002 Fiat Stilo Dynamic,2002 Fiat Stilo Active,2002 Fiat Stilo Abarth,2002 Fiat Stilo,2002 Fiat Simba Concept,2002 Fiat Palio Weekend,2002 Fiat Palio,2002 Fiat Multipla,2002 Fiat Albea,2001 Fiat Doblo

 

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