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Discussion Starter #1 (Edited)
--Updated 6/1/2012--
One of the codes came back yesterday, the P2112-Throttle Actuator System Stuck Closed. I stopped for coffee yesterday and when I started back up, it was running really rough, the message said 'Engine in Reduced Performance Mode' or something and the Check Engine and ! lights came on. I shut off and restarted it and it idled fine, but the lights stayed on. I had Autozone read it and just the P2112 code came up.

Any advice on the next steps? I have it scheduled for the shop on Tues, but I'd like to see if there's anything I can do over the weekend, or at least have an idea of what needs to be done. Any thoughts much appreciated. Thanks,

Eric
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I paid $91 for a diagnostic and I don't feel like I got much out of it. Here's what happened.

The yellow triangle light came on and a message about needing engine maintenance. I figured someone had forgotten to reset the timer and it was just telling me I was due for an oil change.

I took it to my service guys. It's a higher end import shop I've used for years. They tell me that as soon as they started it they could tell it was in 'limp home' mode. Which is odd because it seemed fine to me for the week the light was on.

Anyway, they scanned it and came up with P2112 - Throttle Actuator Control System Stuck Closed, 4050 - Fuel Level Sensor Faulty Signal, 91C7 Throttle Valve Faulty Signal and a few less concerning ones CCM-0021 Air Quality Sensor, DDM-002B Mirror Motor MC Signal Too Low and SUM-0244 Control Module Internal Fault.

So they poked around looking for vacuum leaks, throttle body leaks and sticky valves and didn't find anything. They reset the codes, it came out of limp mode, the light stayed off so they sent me on my way.

How concerned should I be? Oh, it's a 2004 V70R with 113,500 miles. If these codes come back, where would you begin? Thanks in advance for any thoughts you can share.
 

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Alternator? Thats a lot of seemingly unrelated mess.
 

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hows the battery? Still the original? Seem like a lot of unrelated sensor issue (as mentioned by vLGrok) which can be a sign of a weak battery. I'd have that checked before throwing parts at it.
 

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For an 04 R, the generic P2112 code translates to the following volvo-specific code: ECM-91C7.

Here is what the volvo diagnostic software (VIDA) says about the ECM-91C7 code:

Diagnostic trouble code (DTC) ECM-91C7 is stored if the engine control module (ECM), when attempting to adapt the throttle unit, registers that the movements of the throttle is impeded or that the opening spring in the throttle unit is not functioning correctly.

Possible source

Faulty signal:

The throttle is sticking or is blocked (oil film, dust etc.)
Contact resistance or oxidation in the terminals between the engine control module (ECM) and the throttle unit
Open-circuit, short-circuit to ground or short-circuit to supply voltage in the wiring for the damper motor in the throttle unit
Short-circuit to each other in the wiring for the damper motor in the throttle unit
Defective throttle unit.

You can try pulling the electronic throttle body unit (located under the intake manifold) to check if the throttle plate is gummed up with oil deposits. KillerB posted some good information about pulling and cleaning the throttle body unit in this thread: http://forums.swedespeed.com/showthread.php?141305-Bad-MAF&p=1521506&viewfull=1

If you're going to pull the throttle body unit, I would recommend using a new gasket when you re-install it.

There are additional procedures for checking the resistance of the throttle body unit inputs available in VIDA, but I would suggest trying to clean the throttle plate as a first step.

Cheers,

Jeff
 
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