How I Cleared My CEL or MIL For P2101 P0638

[gmcjetpilot]

Edit How I did NOT clear CEL/MIL - Still Issues after replacing 03G 128 063T

I had these two faults (below) which triggered a flashing glow plug light (GP Lt) on
occasion, once every 3-6 months. This has been going on for almost two years,
only after a cold start. It would always reset once I shut down and restarted. I was
getting the GP Lt. flash more often and even during driving for a split second. Then
the MIL came on yesterday, stayed on. GP Lt. flash reset. I had already purchased
a new Anti-Shutter/Throttle Body. I installed it today, but the <MIL> would not go out.

I tried clearing codes with RossTech. I tried the 10 min battery disconnect. Then I
went for a drive, still MIL on solid. I connected RossTech and did a input/output
test of the throttle body. Not sure what it does, but it looks like it cycles it, open
and close. I did that a few times. I went to "Readiness" and MIL status was OFF?
Humm. Sure enough I rest the <MIL>. Just took it for test drive, all is good!!!

Does anyone know what I did? I think the "test" reset it. I know reading some
of the Ross Tech Wiki's there are some weird reset procedures.

2 Faults Found:
008449 - Throttle Valve Actuator Control System
P2101 - 000 - Malfunction - Intermittent

001592 - Throttle Body Actuator Bank 1 (J338)
P0638 - 000 - Implausible Signal - Intermittent - MIL ON

 

[gmcjetpilot]

Well I spoke too soon. I cleared the MIL and then driving it flashed on and the MIL came back. Not sure if I have to do some adaptation alignment with my Ross Tech. Reading the codes it could be throttle sensor or EGR? Any ideas?

I think these might be false alarms.... The old Throttle body was clean and looked like it was free moving.

 

[Ol'Rattler]

The valve you replaced is not a throttle valve. it is an anti shudder valve and all though it looks like a throttle it's purpose is to regulate air for the EGR and to prevent shudder when the engine is shut down.

On a TDI acceleration is controlled by regulating the fuel not the air.

 

[gmcjetpilot]

The valve you replaced is not a throttle valve. it is an anti shudder valve and all though it looks like a throttle it's purpose is to regulate air for the EGR and to prevent shudder when the engine is shut down. On a TDI acceleration is controlled by regulating the fuel not the air.

Thanks, right understood all that... It is called even on VW OEM parts sites "EGR modulator", "Exhaust Back Pressure Regulator", "Fuel Injection Throttle Body", "Regulator" and as you call it anti-shutter valve (for smoother shut down), typical P/N: 03G 128 063T. As you said it regulates intake during Re-Gen to raise EGT.

Going in the nomenclature from Ross Tech VAGCOM error codes:
008449 - Throttle Valve Actuator Control System P2101 - 000 - Malfunction - Intermittent
001592 - Throttle Body Actuator Bank 1 (J338)

I understand "P2015 intake manifold flap; implausible signal" is the actuation of the butterflies (flaps) in the intake manifold.
There is some over center issue, over time that, can be fixed with an extra stop. The alternative is replace the manifold assembly.
http://forums.tdiclub.com/showthread.php?t=418195&highlight=manifold+flaps

I don't have P2015.... this is why I thought it was the "shutter valve". It seems like it wants to correct it self. I am going to try
"adaptation" and see if I can clear it. I am willing to try anything. Suggestions?

Issue from my research can be one of these:
Pedal position sensor malfunction
Throttle position sensor malfunction X
Throttle* actuator motor malfunction X
Dirty throttle body* wiring harness
Loose or dirty connections PCM/ECM Malfunction
References:
https://www.obd-codes.com/p0638
https://www.obd-codes.com/p2101


* The mention of Throttle to me means the anti-shutter. By replacing 03G 128 063T I eliminated two of these. I am going to clean the electrical connections and then look at Pedal position sensor....

 

[gmcjetpilot]

OK round two. I was able to do Throttle Body Adaptation, and while I was at it did EGR adaptation.

I cleared the faults and MIL with the Engine, clear fault button. Frankly I did not know about this selection. I had tried to clear fault with AUTO SCAN, Clear All DTC's (Diagnostic Trouble Codes). That would not clear these engine faults. You have to go to the ENGINE settings and clear faults.

Well it was great for about 20 miles, and under some spirited acceleration I got on flash of the glow plug and MIL came on again. Hummm. I did not read the fault yet, but assume it will be the dame. I am at work and don't have my Ross Tech/Computer to read DTC yet.

 

[gmcjetpilot]

Well partial success. No MIL but when driving today the glow plug light flashed for a split second. I did a bunch of Ross Tech adaptation, clearing DTC faults. However in readiness, it has EGR failed or not completed. So I am thinking the EGR is doing something strange.... However I am not getting specific EGR DTC faults.

 

[gmcjetpilot]

Well it came back... including MIL or CEL. I said heck with it. I kept driving for
the last 2 weeks. IT CLEARED ITSELF! The MIL/CEL is now out.

After driving a short distance, under light to medium acceleration I'd get the
chime and "check engine" MFD message would flash. After it did this for a
week or two, almost every other time I drove te MIL/CEL came on. Now as I
say it is out and I did not clear it!

008449 - Throttle Valve Actuator Control System P2101 - 000 - Malfunction - Intermittent
AND
001592 - Throttle Body Actuator Bank 1 (J338) P0638 - 000 - Implausible Signal - Intermittent

I replaced the throttle anti shutter valve and that seemed to fix it, but it came
back and threw MIL/CEL which I cleared twice. It came back and cleared by itself.
Something subtle? Anyone?

 

[meerschm]

you might have a loose wire someplace

 

[gmcjetpilot]

you might have a loose wire someplace

Thanks Mike! I have been enjoying the light show. It cleared it self. Then it came back. It is always after starting, driving, light acceleration, "DING" quick flash of glow plug which extinguishes, quick MFD message check engine. I am going to plug it in tomorrow ... The codes as I read, can be related to:

• Pedal position sensor malfunction
• Throttle position sensor malfunction
• Throttle actuator motor malfunction
• Dirty throttle body* wiring harness
• Loose or dirty connections PCM/ECM Malfunction

As you said could be a connection... Cheers...

 

[calimustang]

Any luck?

 

[jetlagmech]

When I had the p0638 code, I cleared it, came back week later, cleared again and it came back the next drive with flashing glow plug light and limp mode on highway to work. I cleared again and drove home with lights flashing but not in limp mode anyway.

removed throttle valve, cleaned and lubed. just behind radiator on pipe coming up from intercooler. its been 3 months and no problems since.

During the ordeal I did get a couple other codes caused by the valve sticking. EGR excessive flow and another but I don't remember what now.

When I removed the valve it would barely move with my fingers, a lot of build up around the butterfly seat. after cleaning and lubing it moved easily with my fingers.

 

[jetlagmech]

had the P0638 come back again this last weekend. after it dropped into limp mode it also threw P2015 intake valve, turbo underboost, #3 balance. and then it quit and I coasted to side of hiway. I cleared the codes and banged on the side of the P0638 intake valve, no start. then I banged on the intake valve with the key on, then it started and I got it home in limp mode. removed the valve and it was very stiff and sticky moving the butterfly. sprayed some penetrant on the bushings and opened the edge of the box with the gears and motor and sprayed some lube in there and worked it a few times. Within a few moves it was smooth and easy. driving fine now.

with this valve on the intake, I didn't think I needed to worry about using hi-temp lube on it, but maybe that's whats needed. didn't have any in my garage at that moment. will see if it only lasts 4 months again.