The car, an 03Q with 56K miles, had no problem until I did the Throttle Body cleaning. As part of preventive maintenance, every 2 years, I clean the TB, ATF fluid exchange, brake pads check & fluid flush, gear oil change, P/S drain and refill, radiator flush, etc.

After taking out the air intake duct, the I found out the TB was still very clean but cleaned it anyway. Then I removed the connectors besides the TB (Throttle Control Actuator), cleaned with contact cleaner and then applied dielectric grease. Drove the car for a couple of days fault-free, then CEL came on with DTC P0507-Idle Speed Control problem (more than 25RPM over programmed Idle RPM). Per FSM, problem could be with Electric Throttle Control Actuator; Intake Air Leak; or PCV System. I disassembled the intake duct, checked for any leak source and re-assembled. Per FSM, RE-LEARNING is required any time the Throttle Control Actuator or ECM is disconnected, duh. I did the Gas Pedal and Throttle Valve Closed re-learning and then IAVL (Idle Air Volume Learning). Per spec, Idle at Park/Neutral and NO LOAD should be 650+/-50 RPM. Although the CEL came off, the lowest I can get was 750 RPM. I drove the car for several minutes then as soon as I parked, CEL came on again, same DTC code.

From internet search, I found out that this is a common problem (IAVL Fail due no-load Idle >725 RPM)) with 2002-2005 Nissan and Infiniti - Nissan TSB NTB05-067 and Infiniti TSB ITB05-042. On another Infiniti forum (not NICO) a member posted that it can only be corrected by ECM re-programming, $200 at dealership. Really???

Is there any one who has a complete copy of the TSB? Should I bite the bullet and take it to the dealership? I know my PCV is good but I will replace and re-check before going to the dealership.


Modified by loystock at 4:13 PM 8/10/2009

I'm pretty sure thats your only bet....

too bad your not on the east coast, my shop can update all ecms for $150

Here is your answer, Also check for vacum leaks and electrical plugs are all connected.

Cheers!

Idle Volume relearn Witout Consult2.

It is better to count the time accurately with a clock. It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit has a malfunction.Perform "Throttle Valve Closed Position Learning". Start engine and warm it up to normal operating temperature. Check that all items listed under the topic "PRE-CONDITIONING" (previously mentioned) are in good order. Turn ignition switch "OFF" and wait at least 10 seconds . Confirm that accelerator pedal is fully released, turn ignition switch "ON" and wait 3 seconds . Repeat the following procedure quickly five times within 5 seconds . a. Fully depress the accelerator pedal. b. Fully release the accelerator pedal. Wait 7 seconds , fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL goes off. Fully release the accelerator pedal within 3 seconds after the MIL goes off. Start engine and let it idle.

Wait 20 seconds .

Rev up the engine two or three times and make sure that idle speed and ignition timing are within the specifications. If idle speed and ignition timing are not within the specification, the result will be incomplete. In this case, find the cause of the problem by referring to the "Diagnostic Procedure" below.

Thanks you for your input, xerexabante. As in my original post, I have completed Gas Pedal, Throttle Valve Closed and Idle Air Volume Learning but unable to meet the Idle NO-LOAD spec of 650+/-50 RPM. The lowest I can get is 750-800 RPM. The DTC P0507 is generated whenever the actual engine Idle RPM is 25 more than the ECM target RPM. Since the lowest I can get is 750 RPM, then it's more than the high-end side of the spec window + 25 RPM. I reset the ECM and the CEL has remained off for several days now. But I expect it to come on again since the Idle No-Load RPM is still 750 or higher.

The air inlet duct downstream of the MAF sensor is tight. All connectors are secured and I applied dielectric grease. I pulled out both PCV valves and did a 'rattle' test and cleaned them. I also checked/cleaned the PCV tubes and hoses. All are in good condition. But I'm still ordering a pair of PCV valves from IoS, just to make sure.

Does anyone has a copy of the Infiniti TSB ITB05-042. The 03Q is part of the Airbag Recall so I'm taking it to the dealer soon. It would be better if I have a copy of that TSB so I can better explain to them about the high Idle RPM problem..

I'm here at Beshoff Infiniti-San Jose for almost 4 hours now. They have already corrected the SRS recall issue and is now working on the IAVL re-learning. I have printed a copy of ITB05-042 and it clearly states there that IAVL is needed as a result of TB cleaning or disconnecting the ECM.

Per technicians in here, there is a special coating (anti sludge) on the Throttle Body and Plate which can be removed during cleaning. They said that in some cases, ECM re-programming may not work if the TB is 'very clean.' Last time, they have to apply a certain amount of coating (paint?) to get the car to idle per spec. Really weird.

I searched other forums and in the "maxima.org" there is a posting there that per Haynes manual, the TB is coated with sludge-resistant material to protect the bore and plate. Cleaning the TB may impair the engine performance.

In another forum (ford), it is stated that the Ford TB housing has a sticker which stated that the TB should not be cleaned.

Can anybody chime in about this issue? I've been doing TB cleaning for a long time on all the cars I've owned and this is the first time I have encountered this issue.

I can recall as far back as 1989 that Infiniti has such a material on the 1990 Q45 plenum only.

I know that from Berner's (Unknown007) pictures of when he did his plenum job!

But I am not familar enough with the F50 to really help you, Sorry.

But when you cleaned the TB, How dirty was it before the cleaning?

Previous cleaning was in Aug' 07 and no problem was encountered. This time, the TB was still clean so I just did a bit of cleaning (never sprayed on the body itself but on the rag). With so much time to spare, after cleaning the MAF sensor, I disconnected the Throttle Actuator connector and applied dielectric grease.

It was only after a couple of days after the TB cleaning that SES turned on and got this code P0507. So I followed the FSM procedure and completed Gas Pedal and Throttle Valve Closed Learning and the Idle Air Volume Learning (IAVL). I cannot get the No-Load speed of 650+/-50 to spec.

Still here at the dealership, almost 5 hours now. I'll probably go home unless they can resolve it the next 30 mins.

Latest update...ECM re-programming has been completed but they cannot get the Idle spec. Service adviser is now recommending TB replacement. Wow!!!

I'm going home and think about it.

The power of reasoning and a little bit of luck....

In essence, the dealership is saying that I shouldn't have cleaned the TB since it is not recommended by Infiniti nor was the usage of any additive in the car. I told them that nowhere in the car manual nor FSM where it is stated TB cleaning is not allowed. As for the after-market additives, it was a generic statement, mainly a CYA for Infiniti at the same time encourages customers to buy additives only from the dealership.

The SA was about to send me home but I told him I need a quote on the TB R&R and that it should be covered by the Powertrain warranty (6/70K) and CA Emission Warranty (7/70K). The in-service date of my car was 14Sep03 and presently has only 56K miles in it. So it should still be covered by both warranties. The SA was surprised by my statement. So he left his office and a few minutes later came back with a 'thumbs-up.'

They have ordered a new TB assembly and will REPLACE IT FOR FREE, under warranty. They will give me a call once the TB has arrived.

In all sincerity, the SA, Bernardo Zeballos and the technicians, Suhaib and Rigo did their best to help me. They re-programmed the ECM and did IAVL several times but just can't get it to spec. I watched them as they re-checked the intake, TB, PCV system, etc. all in vain. BTW, their service area is the cleanest and most organized shop I've ever seen. And their customer lounge has 2 computers available for use by customers. And they will add some more in the near future.

Paul Wall wrote:I can recall as far back as 1989 that Infiniti has such a material on the 1990 Q45 plenum only.

I know that from Berner's (Unknown007) pictures of when he did his plenum job!

You may be the only one who can recall such a fact.

The second sentence makes no sense!

As the old expression goes, if it ain't broke don't fix it.

maxnix wrote:You may be the only one who can recall such a fact.

The second sentence makes no sense!

OK I said that because I saw some gold (paint?) on the inside of the plenum, and Berner did say that it came off as he cleaned it. So it may have been something that prevented bulid up of what ever got through the air filter.

And I know he did'nt do a NICO plenum job or hell even a right one but he still removed the plenum.

That adage "As the old expression goes, if it ain't broke don't fix it." applies to some machineries and appliances. I will always do preventive maintenance in my cars. I have never been stranded on the road for my actions (knock on wood).

I was in the airline industry for 18 years as an avionics engineer/trainer/consultant/manager and even worked on large GE, Prattt & Whitmey and Rolls-Royce aircraft engines and related controllers. Had we waited for things to break down, lots of planes would have been dropping like stones from the sky.

I switched to semiconductor industry 13 years ago. Same thing - without preventive maintenance maintenance on wafer processing equipment ($1M-10M each), Intel would never have had success with Copy-Exact and chips from Intel, IBM, TI, Samsung and the likes would be behaving like dysfunctional families.

loystock wrote:That adage "As the old expression goes, if it ain't broke don't fix it." applies to some machineries and appliances.

Doesn't even work for most statues.

The TB was replaced this afternoon at Beshoff Infiniti. TB R&R, ECM re-programming and IAVL completed in less than an hour. Not a single cent out of pocket for all the work they have done, including the 5 hours last Monday.

I'm very pleased with the service.

Your a very lucky person.

Next time be careful about what you clean and how you clean it.

Put in a new air cleaner, thought why not clean the throttle body. Coded. Read forum. Just spent $450 on the new air cleaner and now this. Glad I didn't go all the way and do the plugs also. I'd probably be looking at new coil packs and wire harnesses.

Have you tried the idle relearn procedure? When I did this on my G35, disconnecting it always resulted in a code and the need for a relearn.

I reset the code, then after a few days it came back. Drove perfectly during those days. I just tried the relearn. The MIL turned off during the procedure, then after I started it was basically blinking on and off while revving a few times. Turned it off, and still pulling code. If I replace the TB will I need an ECM reprogram? Looks like I can get a new TB on ebay for $125.

I'd try it a few times. At least on my G it didn't always take the first time. I don't think the reprogram would involve reprogramming the ECU. If the eBay TB is returnable, it might be worth a try, but I don't know how successful aftermarket parts are for this type of thing