OBD codes P1029 and P1031.....

MikesS70 · Post by **MikesS70** » 16 May 2009, 20:31

Car is a '99 S70 non-turbo I-5 ....Engine runs rough ...feels like it's running on 4 cylinders.

Had suspect coil pack that was swapped with new one condition remains the same.

CEL is on with codes P1029 and P1031. ...these were downloaded with a generic handheld scanner (not Volvo specific).

Can anyone tell me, specifically, what these codes pertain to?

Thanks,

Mike

Post by **MadeInJapan** » 16 May 2009, 21:44

P1029 Intake manifold air control valve position sensor - upper limit not reached
P1030 Intake manifold air control valve position sensor - lower limit not reached

Is your idle air control unplugged?

MikesS70 · Post by **MikesS70** » 17 May 2009, 05:38

MadeInJapan wrote:P1029 Intake manifold air control valve position sensor - upper limit not reached
P1030 Intake manifold air control valve position sensor - lower limit not reached

Is your idle air control unplugged?

Good question if I knew where to look for it.....I can find it on all my other non-Volvo vehicles. My car has the ETM and unless the IAC is up underneath and behind it somewhere it doesn't look like my car has one.

Other codes that have popped up are P1017, P1021 and P1026 ...these codes came up a initially when I first started having these idle issues but have not shown up since I cleared them. Codes 1029 and 1031 persist and cannot be cleared by my handheld scanner.

The car is basically undriveable. It will idle steady but rough and when revved a little will spin up but have a very spastic return to idle. The engine has no power ...it can be moved but it seems there is no solid response to pressing the accelerator.

Mike

Post by **vegasjetskier** » 17 May 2009, 05:46

The IAC is component G in this illustration:

S70ComponentLocations1999.pdf: (47.55 KiB) Downloaded 507 times

Post by **MadeInJapan** » 17 May 2009, 05:53

Yours is a bit different, but VADIS shows an idle trim control- #12 in this diagram- maybe the wire is disconnected?

: Idle Trim Control.jpg (146.67 KiB) Viewed 5081 times

Post by **vegasjetskier** » 17 May 2009, 06:11

Is this it?

Post by **MadeInJapan** » 17 May 2009, 06:52

Yes, that's it...but I believe the '99 is a bit different..there wont' be a connector plug but more of what looks like a grounding wire with an eyelet at the end of the wire (I think)...I would take it off, clean it thoroughly and tighten it back down. With your car's key at position II (not started yet), it should be buzzing, so that's a test for you on that part.

MikesS70 · Post by **MikesS70** » 17 May 2009, 18:50

Thanks to all for your inputs. I'll have to look ...if there is an IAC it lives up behind the ETM out of sight or it's located on the fan shroud/radiator mount (which I doubt) but I'll poke around. I'd love to find a simple fix but I'm not gonna hold my breath on this

I decided to sign up for the AllDATA-DIY subscription for the S70. According to their OBDII SAE/ISO to Volvo DII DTC code converter, the two OBDII codes convert to ECM-914F and ECM-9190 respectively with "ECM" standing for Engine Control Module. The codes break out as:

P1026/ECM-914F Throttle Unit, Internal Fault
P1031/ECM-9190 Throttle Unit, Internal Fault

Under "Fault Type", both DTC's are classified as "faulty signal".

The other codes I got initially, which were cleared and have not returned, were P1017, P1021 and P1081.

P1017/ECM-900E Engine Control Module, internal fault
P1021/ECM-903F Throttle Unit

Again, these are both atributed to "faulty signal".

The P1081/ECM-720A Immobilizer Communication is either a faulty or no communication cause.

So it would seem my troubles are centered around the "Throttle Unit" having an internal fault due to receiving faulty signals. I'm wondering if my cleaning of the ETM didn't cause some internal damage or speed up its inevitable failure.

My local Volvo dealership fell under the axe of the very quiet cut back, by Ford Motor Co., of many Volvo dealers in an effort to cut costs. My only alternative is to find a local shop experienced with Volvos...... As much as I'd love to be able to enjoy the "Eureka Moment" with my car....I'm afraid I'm going to have to cry "uncle" pretty soon and bring it in for a professionsl diagnosis..... I'll see what I can find with AllDATA and of course any suggestions you all might come up with.

Mike

Post by **vegasjetskier** » 17 May 2009, 19:04

Did you test the #5 fuel injector?

MikesS70 · Post by **MikesS70** » 17 May 2009, 19:35

vegasjetskier wrote:Did you test the #5 fuel injector?

No I haven't. After reading the Volvo info on AllDATA, if the coil pack and/or injector were causing a misfire, there should be a trouble code indicating a misfire. Given how rough the engine idles and if it was a misfire then a code should have been set.

The car has been out of commission for about a week now ...and it will need to be towed to the shop as driving it the distance would not, in my book, be wise. I'm not so sure tearing into the injectors would be to my benefit. I may invest in a "noid" light to check electrical impulses but I'm not going to go much further.

The majority of the codes set so far have centered on the ETM and either faulty signals or internal faults.