Help this SHO code first timer out.

[MelectroK]

Ran my codes for the first time. It simple as **** to do. Maybe some of you can help me with a few things here.

The reason I ran the codes was because 3 times now, my check engine light has came on very breafly. It when its cold in the morning. I would start the car and let it run for about 5 minutes to warm up. Its been between 25 and 32 all night long. I get in and start driving. I drive about a 1/2 mile and the CE light will come on. It will stay on for about 2-3 minutes then turn off usually about 2 miles later.

When I ran codes I get memory codes of 173, 177, & 528.

173 - Oxygen sensor not switching - system is or was rich - Single Right or Rear HO2S

177 - Oxygen sensor not switching - system was rich Left or Front HO2S

528 - System shows voltage at pin 10 (is A/C on ?) or pin 30 (PNP CPP switch)

Now if I would have gotten a 173 or 177 alone I would think its a bad sensor, but with both of them I would assume that they are fine and the actual car is running rich. (I dont know what to think about the 528). Now, where would you guys and gals think to start with this problem?

A second question I have. I ran the codes when the car was cold from sitting all nights, cuz I didnt care about the current readings. But I still got a 116 and a 114.

114 - IAT sensor out of range - IAT

116 - Engine Coolant (ECT) sensor out of range - ECT

Now did I only get these because the car was cold, or are they related to rich problem?

Thanks for your help alls.

 

[rangerj]

5 minutes is not enough time to warm up. The car should be at normal operating temperature when codes are checked. When it is not warmed up the IAB is partially closed to cause a rich condition, like a choke on a carb. So, until it is warmed up it is running rich.

That haviing been said, you got your codes from the memory, as opposed to "real time" codes. It is not unusual for equally old O2 sensors to fail about the same time. 60K is about the normal life expectancy for an O2 sensor. The sensors usually do not fail all at once. They usually slow down on the number of switches (from rich to lean), then they will stick in the rich or lean mode, switch for awhile, then stick again, etc. This may be why you get your on and off "check engine" light while driving.

The computer "codes" when it does not get the signal it expects from a given sensor. The cause can be a failed, or failing, sensor, a poor connection, or a short or "open" in the wire between the sensor and the computer. So, make sure your O2 sensors have good clean connections. Then clear the codes and see if the codes return.

If you have access to a scanner that enables you to see what the sensor is doing in real time, you could watch the sensor "switch", or not switch. It should switch rapidly and continuously from rich to lean. If this is not an option do some checks for a rich condition, such as black exaust smoke,
black deposits on the plugs (pull a couple).

The 528 code is a clutch switch circuit failure (A/C clutch?). If the A/C was not on this code is not meaningful and can be ignored.

This may not prove much because when the O2 sensors do not give the computer the information it expects the computor is programmed to richen the mixture to protect the engine. A lean condition can burn valves, cause serious over heating, etc.

So, if the codes are cleared and they return I would suspect the O2 sensors. If they have 50K or more miles on them, I would change them (60K is the recommended change interval). You could try changing one of them and see if that bank(front or rear) returns to normal. You could also clean the IAB to make sure it is not causing any air flow restriction. Check your air filter and the other components to be sure air flow is not restricted, which could cause a rich condition. rangerj

 

[MelectroK]

checking the plugs for black deposits is to determine if the engine was actually running rich as oposed to a bad sensor?

 

[rangerj]

Yes, black sooty plugs are a sign of an engine that is actually running rich. You want to determine if the O2 sensors are feeding the computer false information, or are the sensors feeding the computer the correct information.

If the sensor is stuck (not switching) on "lean", then the computer tells the injectors to spray more fuel into the cylinders. The fact that the computer coded indicating a lack of switching by the sensors tells me that the connection and wires between the computer and the sensors are good.

So, why aren't the sensors switching? Is the car actually running rich due to restricted air flow, poor spark plugs or wires, or glogged injectors that are not closing, or are you actually running lean due to a vacuum leak?

If you are not seeing black smoke coming out the exaust, especially upon acceleration, you are probably not running rich. rangerj

 

[MelectroK]

Had the same problem again. 30 degrees outside. Warmed the car for 4 mins. 1/2 mile down the road CE light comes on. Stays on till temp gauge gets to the line just passed the C. Now I know the car is suppose to run rich when its this cold. But its eather running to rich or the O2 sensors are not warming up properly. I will check the codes when i get home to see what the problem is.

 

[MelectroK]

Okay got home ran codes. Got a 114 for a hard code, and got a 173 and 528 for a memory code. This time the car was all warmed up.

This time the only O2 sensor that faulted is the right (rear). Unlike the first time when I had both of them faulted.

But Im still curious. I got the 114 again which is IAT sensor out of range. Now does IAT stand for Intake Air Temperature, and is this the sensor that is mounted in the air intake box by the filter?

Im just kinda curious to if this sensor being bad would cause the car to temporily run rich and to trigger the out of range readings on my 02's?

Now am I correct in thinking this sensor may be bad because I didnt receive a 112 or a 113 which covers eather a shorted or open circuit. Or could it still be the wiring. Or is it something to not worry about at all.


I was told to remove the plugs and check for black but if the car is only running rich while the light is on for about 2 minutes then by the time I get to work and then drive home and remove them, the black would be burnt off.

Can anyone steer this SHO owner in the right direction please.

(PS) Another post had mentioned that you get a 114 when the temperature drops below 40 degrees. Is this correct and the only reason for the 114 code?

 

[rangerj]

Code 173 indicates that the O2 sensor is not switching as frequently as the computer thinks it should (programmed to expect continuous switching from rich to lean and back). The questions then are; 1. is the O2 sensor failing, 2. is the engine actually running either rich or lean for long enough periods for the check engine light to be triggered and a code to be stored.

If the computer can tell that the O2 sensor is not switching, or switching slowly, then the connection and wires are OK.

If you are not actually running rich, or lean, for long periods then the O2 sensor is failing or has failed. The O2 sensors do not usually fail all at once. They go bad over time, which is most likely why the recommended change interval is 60K. The signs of failure are usually; slow switching, or stop switching all together.

The 114 code is relative to the Air Charge Temperature sensor (IAT is the 1993 and later terminology) The sensor is located in the air cleaner assembly. The code is triggered if the resistance (in ohms) and voltage is above or below the amount programmed to be expected. In temperatures below 45 or 50 degrees F this code is not a cause for concern.

The voltage and ohms range for the sensor is 50 degrees F to 248 degrees F. The resistance ranges 58.75K ohms and 3.52 Volts at 50 F, and varies down in volts, e.g. 0.28 V at 248F. The ohms at 248F will be lower at 1.18K ohms. So as the temp goes up the Volt and Ohms resistance goes down.

But, below 50 degrees F the sensor is going to code "out of range". Not to worry!

So, if the O2 sensors have 50K or more on them I would replace them. If they are new then they are less likely to be the problem, and further diagnostics are necessary, e.g. look for signs of rich conditions such as black soot build up on the plugs or black exaust gas. rangerj