My son took his car for emissions testing and the OBD said that 4 readings were "not ready". Catalyst-N, Evaporative System-N, O2 Sensor-N, EGR System-N. They told us to take it to a saturn dealer that could read them. Without doing the diagnostic check, do you think we are looking at spending alot of money to fix these problems. The diagnostic check is $95.00, then whatever else it will cost to fix.
I cant solve this problem but I am having the same problem, same codes, and it was reving high just like another post. My check engine light has never came on and it failed the test. Im going to Auto Zone however the last time I went by they would not stick it on on dio. test becsue the light was not on. Did they ever stop to think the light might be burned out? Of course not, I'm a girl why beleive me.
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For OBD 2 there are thing's the cars computer check's for emissions , there called monitors . When these monitors run an set the vehicle will be ready to pass an emission test . OBD Readiness Monitors Explained OBD Auto Doctor Scantool Garage Read this if you would like to know more . Normal driving will set the monitors in time or you could try an speed up the process with a drive cycle
OBD II P0157 due to Oxygen Sensor Circuit Low Voltage (Bank 2, Sensor 2)
This code refers to a fault in the post-catalyst o2 sensor on Bank 2. First, a basic run-down of the catalyst: The Catalytic Converter is used to help control tailpipe emissions, to "clean up" the exhaust, if you will. The PCM (Powertrain Control Module) uses the signal from the heated oxygen sensor to the rear of the catalyst to monitor the catalyst's efficiency by comparing it to the o2 sensors in front of the catalyst.
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Definition of P0420 is catalyst below threshold. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). Catalytic converters are not normally a "wear" type item, that is they are not deisgned to wear out and need replacement. If they have failed, it is likely due to something else that caused it to fail.
P0447 Evaporative Emission Control System Vent Valve/Solenoid Circuit Open. The Powertrain Control Module (PCM) has detected an open within the circuit that controls the vent valve or solenoid for evaporative emission systems vapor.
drive it. I am betting you have recently "cleared" codes which also clears readiness monitors in an attempt to better control people cheating the system. After enough drive cycles are reached the monitors will pass if nothing is wrong and turn to ready. If the problem that the codes implicated where not fixed than the check engine light will again come back on and you will again fail your attempt to pass emissions.
Your vehicle is equipped with an OBD II computer AND a link to connect OBD II computer to a Smog Check Analyzer or Data Scan Tool (available
at most auto part stores).There are two types of codes, bad codes and good codes. The good codes are the "Readiness Flags". These Readiness Flags
indicate that certain emissions systems which the OBD II computer has been monitoring have PASSED the test, indicating that those systems are
working properly. Then there are the bad codes. The bad codes are actual "Trouble Code". These codes indicate that the OBD II computer
has detected a problem with in the emissions system. The Trouble Code will specifically indicate the component and problem which was found.
Newer vehicle's have very complex codes in the thousands.
"Readiness Flags" do not cause the "Check Engine" light to illuminate, but may cause a vehicle to fail the smog test.
In order to set all the proper "Readiness Flags" the OBDII system must complete at least one drive cycle (in some cases
two or three). A drive cycle is a sequence of internal tests which the OBDII computer runs while your vehicle is being driven. This insures
all emissions systems are functioning properly. Only then will your vehicle pass the smog inspection. A drive cycle usually requires one
week of driving.
P0401 is EGR valve, low circulation detected. P0420 Catalyst system. P0133 is O2 sensor bank 1 sensor 1. All these codes are emissions related, so i would start with the EGR valve, it's probably clogged with carbon. The catalytic converter could be also, check that for excessive backpressure. The oxygen sensor can be tested, replace if needed. Good luck, i hope this helps.
Some models have two sensors, one before the catalyst and one after.
This is done for a catalyst efficiency monitor that is a part of the
OBD-II engine controls. The one before the catalyst measures the exhaust
emissions right out of the engine, and sends the signal to the PCM
about the state of the mixture as previously talked about. The second
sensor reports the difference in the emissions after the exhaust gases
have gone through the catalyst. This sensor reports to the PCM the
amount of emissions reduction the catalyst is performing.
Fig. 4: Typical oxygen sensor locations-3.0L OHC (4 valve) engine (click over pic for zoom)
First the fault codes, U110C is No Fuel Level Bus Message U0155 is No Cluster Bus Message. Unfortunatly you have to be able to communicate with the instrument cluster with your scanner to diagnoise and I do not think an aftermarket scanner can do this.