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YOUR RESEARCH16 fault codes - help appreciated
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Clean +
Performed · outcome unconfirmed
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1
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Performed · outcome unconfirmed · Original poster
I've already cleaned the ICV (cleaned + tested), MAF and TB, and just cleared the codes in my office's parking lot (will drive it home after work).
Leading evidence: 'Clean +' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check cam deviations' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
I've already cleaned the ICV (cleaned + tested), MAF and TB, and just cleared the codes in my office's parking lot (will drive it home after work).
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Performed · outcome unconfirmed
My engine was replaced in �04, but just the short block.
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Performed · outcome unconfirmed · Original poster
Yeah they were replaced 20K miles or so ago but will check the receipts.
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21 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Edit 7/20/22 - Video of rough idle (comes and goes) attached to this post below.
Noticed the car acting up a few hundred miles after my third oil change under ownership. Car was running like a beast - still does - but has a rough-ish idle (gets better with AC on, but one of my condensers leaks so I try to keep AC off).
I've already cleaned the ICV (cleaned + tested), MAF and TB, and just cleared the codes in my office's parking lot (will drive it home after work). I have not checked any voltages anywhere or done any other diagnostics other than hook it up to my Autel Maxidas. I tried actuating the CEL via the Autel but the light did not pop so I think the bulb may be dead...
My car is an 01/98 996
Codes:
P1275 - oxygen sensor ageing delay, bank 1
P0139 - 02 sensor ageing behind cat. conv., bank 1
P0140 - 02 sensor behind cat. conv., bank 1
P1117 - Oxygen sensor heater behind cat. conv., bank 1
P1276 - oxygen sensor ageing delay, bank 2
P0159 - 02 sensor behind cat. conv., bank 2
^^ I've had these codes before. O2 sensors read good voltage but bank 2's lags a tad throwing the delay codes - both bank O2's still function properly.
I have not seen any of these before (except 1539):
1691 - service manual (
edit:
I think this is the CEL bulb...?)
1539 - (have had this one before, went away for a while, no noticeable loss in power - I do not think the solenoid or actuator is bad... could be wrong)
1319 - service manual
1318 - ^
1317 - ^
1316 - ^
P0300 - misfire detection (total)
P0306 - Cyl 6 misfire
P0305 - Cyl 5 misfire
P0304 - Cyl 4 misfire
Codes for locking/alarm system (my car will attempt to lock, then unlock and beep twice):
23 - W lead
33 - passenger compartment monitoring sensor
60 - central locking limit position Lock not reached
58 - Tank servo motor not energized despite relay activation
Might just bite the bullet and do all coils, plugs and all four O2 sensors.
Worried about dumping that money in with no avail because this rough idle popped after an oil change... If it is the bank 2 Variocam solenoid/actuator then I'd rather take the grand and put it towards that.
I think you should investigate your Variocam further before you throw parts at the car. I agree this will just further frustrate you down the road from the expense.
Rough idle? After oil change. Check that the oil filler pipe cap is on tight and check the oil filler pipe for cracks. @110K miles it probably is cracked.
will do.
Real quick do u think a bad ICV could cause a misfire like this? Few months ago I actuated the icv while cleaning it out of the car but only had - I think - a 12v drill battery or whatever� made a little pos/neg thru that but 12v was too much and it sparked/smoked on the first touch. I threw it back in the car though and has been working fine�.. maybe until now?
You might have fried your ICV. Only use a 9V battery to cycle the ICV when cleaning it. Still check your oil filler cap and oil filler pipe. The DME/ECU might be having trouble with idle with no feedback from the ICV, and they may also cause misfires.
Engine should run in open loop right after a cold start. So it it runs rough on a cold start, the O2 sensors aren't necessarily part of the problem. I'm going out on a limb and saying vacuum leak, ie oil filler tube crack like mentioned above.
Out if curiosity, any idea when the ignition coils, spark plugs, fuel injectors, maf and oxy sensors were last replaced? You got alot of codes there. Ignition coils and maf seem to account for an overabundance of codes. Yes, it could be alot if other things. But if they are old, couldn't hurt to replace nevertheless. But admittedly, I replace my Ignition coils, spark plugs and maf on average every 5 years whether they need it or not.
Yeah they were replaced 20K miles or so ago but will check the receipts. The car's been in the family for about a decade so nothing too crazy here I'm sure... I'm thinking this is something that hasn't been replaced yet, or I fried the ICV after actuating it with that 12V like I described above.... They look to be about $150 on Ebay... It doesn't miss in the powerband so I think plugs and coils are fine. +2 on the vac leak now that I'm typing it out, but still think the ICV may be the culprit since that was the only thing I've clearly messed up/damaged with that 12V... Or definitely the fill tube and cap since it happened shortly after the oil change.
If you check for vacuum leaks and it turns out there are none, the coils are a good place to start. I had an entire set of coils go bad after about 15k mi. (2-3yrs)�
Anyone have input on the video? I inspected the fill tube - looks fine. Re-tightened the cap too.
Thinking of getting 6 coils and plugs/changing those just because, and buying an ICV from Ebay for ~$120 versus the ~$600 for an OE unit.
New coils and plugs make sense. Worst case, your engine will run better. Best case, it solves some of the problems. Just save your old coils in case you need to replace or test them in a few years. New Maf can't hurt either since it's linked to SO many cell issues just like the coils. Again, save the old one.
No opinion about buying anything on ebay other than I would prefer oe porsche because it's one less thing to cross of the refresh list that you won't have to worry about for awhile.
Lastly, get this stuff thru FCP euro to take advantage of the warranty, even if it costs more.
My philosophy on the 996 is pretty straight forward: If you nickle and dime parts for the car, the car will nickle and dime you.
cam deviation 1 goes between 5 and 6
cam deviation 2 goes between 13 and 15 (but this is an 01/98 car I don�t think it measures bank 2s deviations - there is something about this and the ROW cars I think not having sensors for bank 2 cam deviation readings - I could be wrong)
o2 sensor ahead of cat bank 1 & 2 has infrequent readings jumping between .08 and .7 volts (think it�s volts don�t remember) while both o2 sensors behind cat bank 1 & 2 always read around .44 and .5 which is good� the o2�s ahead of the cats seem to be a bit all over the place.
also noticed the idle was around 680rpm which is a tad low so thinking the ICV should be changed
thoufhts on the readings?
a couple things, I can get deviations only on bank two with 5.2 DME. Which shows -3.0.
This is a �99� car as well. My engine was replaced in �04, but just the short block.
My 99�s idle without AC on has always been 680.
I think yours is fine at that speed.
The precat O2 sensors should cycle three times a second and swing in voltage from 0.10 volts to 0.80 volts. Your cats depend on that cycling to be efficient.
A worn out converter will cause front and back sensors to cycle at same rate. Converters are measured for efficiency by measuring lag between the two signals.
Try goosing your throttle to 2,000 rpm to get sensors to around 600 degrees. Then check voltage readings. If your post cat readings get stuck I think your cats are not efficient.
That may be where that hollow knocking sound your engine makes is coming from.
