Question about 2004 Ford Explorer
It's a 2004 ford explorer that had stalling out problem. we fixed the other 2 codes po 174 system too lean bank 2 & po 171 system too lean bank 1. now i need help figuring out what the po 0193 fuel rail pressure high input means n what may be wrong.
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Posted on Jan 02, 2017
Two bad O2 sensors is rare. The problem is before the sensor,intake vacuum leak, injector lower o-ring, IMCR stuck open or the control rod is off, vacuum hose(s) off, or MAF sensor. If this has a plastic upper intake, they had problems with o-rings.
Posted on Oct 07, 2009
switch, we run off snitches. 171 174 banks 1 & 2 Lean. Most likely cause are Upper Intake Manifold Gaskets, failed seals. It's not 1990 on. It's 1996 and on OBD2.
Posted on Nov 03, 2009
P174 means Oxygen sensor was slow in switching Single, Right
or Rear HO2S - Fuel control
P171 means Oxygen sensor not switching - system was at adaptive limits - Single, Right or Rear HO2S - Fuel control
for a comprehensive code listing for your car.
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Posted on Jan 08, 2010
These codes mean that the oxygen sensor is reading too "Lean" on both the left and right cylinder banks and the engine control system can't compensate any further to solve the problem. You may have a dirty or failing Mass Airflow Sensor that is miscalcuating the amount of airflow the engine is taking in which in turn can cause both of these codes to set. If the sensor is reporting less air than the engine is actually taking in then the engine computer will add only the amount of fuel it should based on what it was told by the sensor which will cause both cylinder banks to run "lean". There could be something else going on such as having two bad oxygen sensors [very rare] but I do see these two codes together quite often and usually its the sensor that is causing it. Hope this helps a bit!
Posted on Jul 12, 2010
SOURCE: PO 174 Sys to lean
The check engine codes reproted are telling you that the mixture has too much air (lean mixture). Test and eventually repair or replace parts that may be contributing to the problem.
Test fuel pump and fuel pressure. If fuel delivery is not regular or if pump is broken you may get a lean code from the O2 sensors. Fuel pressure is tested placing an hand pressure gauge within fuel lines.
Ensure that distribution is OK and that there is no misfire. In that case you should get a msfire code along with the lean code, but you never know the misfire does not get detected by PCM (main computer).
Check air intake and sensors, if the MAF or AIT sensors are not connected or malfunctioning you can get a lean mixture.
Check the vacuum system. If there is a leak, then the vacuum will be sucking air from the leak and this may return a lean code.
Check IAC and EGR valves.
I think I listed all most common factors that can return a lean code from both O2 sensors ( that tells you that the sensors are OK).
Posted on Sep 08, 2010
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