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Discussion Starter #1 (Edited)
Hi, Today my car's CEL came on and stayed on until I got to work (70 miles) It came on in the evening when driving home but then switched itself off after about 15 miles. When I got home I scanned for codes and I got :-

P0171 Fuel Trim System Lean Bank 1 - This one I understand and need to track cause.

P1172 Rotor Control - I can't find any information on this one - does anyone know what this refers to?

The car is a 2000(registered in Jan so I expect built in 1999) 9-3 2.0 lpt (red DI casstte) with 94000miles (UK Spec)

I also had a look at the long term fuel trim which is 69.5%. This seems a very high figure suggesting car is running very lean (short term fuel trim was between -10 and + 8%)

When scanning the throttle position angle at idle shows 9.8%, and only 90% when fully open. I checked the resistance values at closed and full open - these were in range.

In terms of driving it seems to run pretty well except idle is lumpy and if I am on overrun with the throttle closed and I then boot it the engine initially seems to hesitate badly for a second giving a real jerk.

Recently the car just stopped and failed to start - found to be the DI cassette so a new one was fitted only about 2 months ago.

It was also really bad on idle surging and stalling a couple of months ago - I sorted this by cleaning the idle control valve and throttle body. I also checked for vacuum leaks and found the grommet that the breather pipe goes into the rocker cover was split - now replaced.

I am hoping someone can give some glues or ideas on where to start to sort this one.

Finally which version of the Trionic system would I have?

Thanks
 

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AMcK said:
P0171 Fuel Trim System Lean Bank 1 - This one I understand and need to track cause.

P1171 Rotor Control - I can't find any information on this one - does anyone know what this refers to?
The P0xx codes are generic, but the P1xx codes are manufacturer specific. Here is the actual definition:

P1171 Saab Closed Loop, Lean Mixture

So, basically both codes are telling you the engine is running lean. Among other things, a cracked vacuum hose from the throttle body to the FPR (fuel pressure regulator) can do that, but so can a number of other things which have to do with closed loop control of the A/F mix.

A car built in 1999 which comes with the red IDM (a.k.a. DI cassette) would have the T5 ecu. In Europe, I am not sure.

Good luck!

edit: hmmm, the code in the title of the thread does not match the code in the post! Just in case,

P1172 Saab Closed Loop, Rich Mixture
 

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PMI said:
edit: hmmm, the code in the title of the thread does not match the code in the post! Just in case,

P1172 Saab Closed Loop, Rich Mixture
Ahhh thanks for that - a slpi of the fingers - post edited.

Just to make sure I checked the file I saved when I read the codes and it is definatly P1172. So that means it is both running lean and rich?
 

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AMcK said:
...it is definatly P1172. So that means it is both running lean and rich?
It is possible for the engine to run rich at idle and steady speed, when the air into the throttle body is at vacuum, and lean during acceleration and when on wide-open-throttle.

One possible cause of that is a Fuel Pressure Regulator which does not follow the intake manifold pressure, because the vacuum line which connects the FPR to the throttle body is cracked, or broken. In that case, the FPR does not regulate up and down with the intake pressure, and fuel pressure is too high when the intake is on vacuum, and too low when the intake is at boost.

It is NOT the only explanation, just the one I happen to have experienced myself... :cheesy:
 

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P1172 = Short Term Fuel Trim. Min Value, Air/Fuel Too Rich.

This is the definition I get for that code. My info is from Alldata. I have a subscription for my 99 viggen. I dont know if this will help you or not. should be the same though cause your car is only a year newer than mine.

It appears to be pointing to your Mass air flow sensor OR a leak in a vacum line somewhere.

Open up your hood and take a good hard look at ALL of your vacum lines end to end paying particular attention to the throttle body, mass air flow sensor area, boost control ect. You may luck out and just change a few rubber hoses.
I just went through my whole engine and changed all the vacum lines, some were in rough shape, no holes yet, but the were close.

Give that route a whirl and keep us updated.
 

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kpa2004 said:
No clue, I'm just givin ya what I know. What does the euro model have in place of the MAF?
He made a point of posting it was the LPT version with a red ignition module... I thought it had the older setup, like my 900, and like some early 9-3 models.

Those use a MAP (manifold air pressure) sensor, in combination with the intake air temp sensor, to calculate the amount of air going into the engine. Not as accurate under all conditions, but the MAP is simple and hardly ever fails.

If his car is more like yours, then you are correct, he should look at the MAF sensor too.
 

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Discussion Starter #10
Thanks for replies.

I'm pretty sure it doesn't have an airflow meter - if it does I can't find it.
It does have a MAP though. When I had my scanner connected it showed about 30 inHg without out engine running and around 11 inHg at idle.

Haven't had chance to look in to it further today - hopefully get some time tomorrow

Will report back anything I find
 
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