Cause of P1175 problem

I recently had my check engine light come on (again) and it’s registering a P1175 error (again). This is apparently indicates a problem with the “fuel trim cylinder balance” in bank 2. And according to what I’ve read can be caused by a number of things, such as a faulty oxygen sensor, ignition problem, fuel injection problem, or some other condition.

I say again, because I had it come on about two months ago with the same error and when I took it in they flushed the fuel injectors, which was apparently recommended by bulletin 03-06-04-030H.

Unfortunately the light has come on again, and stayed on. This happened after I stopped to get gas on my 6 hour drive from visiting family in Michigan. Another interesting data point is that this code has been in the warning state in my engine for over a year from what I can tell. I’ve only used my OBD2 reader a couple of times. First was 9/2011, and no problem was detected. Six months later in March 2012, I checked it again and P1175 was a “pending code”. I hadn’t used the reader until this problem. But now, over a year later, the issue has apparently moved from a pending problem to a more serious one.

What this all boils down to, is that I’m asking opinions as to what the problem may actually be. I’m curious at to what could have been so long in developing. I intend to take the car in to get looked at shortly, but in the mean time I figured I’d ask around.

For reference, my car is a 2008 Saturn Aura XE, with about 71K in mileage (over 13k since I got that reading in 2012).

DTC P1175 indicates that there’s a problem with the Camshaft Position Sensor circuit.

Tester

I suggest you have the fuel trim numbers checked to see if that will offer more clues to the trouble. The O2 sensor seems like a good possibility if you want to just make a guess as to the trouble. If both of them are the same you could try swapping them to see it that changes the sides.

Here’s a slightly outdated version of that bulletin

Here are the parameters for setting that DTC

http://service.gm.com/gmspo/mode6/pdf/2008/08%20GRP07%20All%20Engines.pdf

Does the car have any operational or drivability issues?

How is the car running? It would be worth monitoring the short and long term fuel trim on that side in real time to see if it’s way off from the other bank and if the O2 sensor is changing its output the way it’s supposed to.

I haven’t noticed any drive-ability issues. MPG seems to be unchanged. I’m taking it in today to get looked at, so we’ll see if they can identify the problem.

Well I took my car in on the 22nd as I mentioned in my last post. They didn’t find anything, but since I’d already had my fuel injectors flushed, they cleaned the mass air flow sensor, and left it at that. Now 2 days and a bit less than 300 miles later the light has come on again with the same error according to my code reader.

As per oblivion’s comment and in the hope it may prove useful to someone reading this, I checked the code reader data. And it has freeze frame data as follows:

Parameter Description Results
DTC for which Freeze Frame was Stored P1175
Fuel System 1 Status Closed Loop
Fuel System 2 Status Closed Loop
Calculated LOAD Value 69.80 %
Engine Coolant Temp 197.60 °F
Short Term Fuel Trim - Bank 1 3.91 %
Long Term Fuel Trim - Bank 1 -2.34 %
Short Term Fuel Trim - Bank 2 3.13 %
Long Term Fuel Trim - Bank 2 -3.13 %
Intake Manifold Absolute Pressure 26.06 inHg
Engine RPM 1,683.00 rpm
Vehicle Speed Sensor 59.65 mph
Ignition Timing Advance #1 Cylinder 22.00 °
Intake Air Temperature 96.80 °F
Air Flow Rate Mass Air Flow Sensor 4.16 lb/min
Absolute Throttle Position 38.82 %
Time Since Engine Start 793 sec

And here’s the freeze frame data I got from the last time the light came on, about a week and a half ago:

Parameter Description Results
DTC for which Freeze Frame was Stored P1175
Fuel System 1 Status Closed Loop
Fuel System 2 Status Closed Loop
Calculated LOAD Value 54.51 %
Engine Coolant Temp 197.60 °F
Short Term Fuel Trim - Bank 1 2.34 %
Long Term Fuel Trim - Bank 1 -9.38 %
Short Term Fuel Trim - Bank 2 3.91 %
Long Term Fuel Trim - Bank 2 -9.38 %
Intake Manifold Absolute Pressure 23.69 inHg
Engine RPM 2,088.00 rpm
Vehicle Speed Sensor 75.19 mph
Ignition Timing Advance #1 Cylinder 38.50 °
Intake Air Temperature 100.40 °F
Air Flow Rate Mass Air Flow Sensor 4.18 lb/min
Absolute Throttle Position 36.47 %
Time Since Engine Start 736 sec

The LTFT on the second list seem a little high to me. Perhaps the fuel pressure regulator is slightly high or the O2 sensors are a little wacky. The absolute air pressures seem a little high also but maybe those are okay.

I agree, it seems higher on the 2nd one. I was thinking that the cleaning of the mass air fuel sensor helped in that respect, since it’s more like 3% rather than 10% in the more recent listing (the first one). I guess the O2 sensor may be something to get them to look at next.

This is becoming irritating. What’s interesting is that the error is not consistent. It tends to go off after a while. In fact, both times it has disappeared by the time I was able to take it in. And while this leads me to believe it’s not a major problem, it’s certainly an annoying one.