Loss of Throttle issue on my B4 today

OilBurnerDE

Veteran Member
Joined
May 6, 2003
Location
Newark, Delaware
TDI
1997 Passat T-Red
Hello all, been away for most of the summer with little time to poke around the forums to keep up with the community. Need to get back to a few of you who have Im'd me (specially Kooya, since I need to return something to him).

Experience and Oh $HT moment on my ride home tonight (twice) driving along in traffic slowing down, switched gears, let out clutch, go to accelerate and nothing but Dead Pedal.
No throttle response at all. Motor still running, revs when put in lower gear.
I was able to get off the side of the road and noticed my tach at about 1200 rpms. Glow plug light was flashing. I thought I remember getting some throttle control back but don't remember if it was before or after I stopped and then restarted the car. The glow plug light blinked for the remainder of the commute.

Decided to brave Blue Route congestion and continue on, nervously. Car ran normally, although I did not really push anything, till my exit on the highway. Where it again gave me no acceleration when I needed it most. After almost getting rear ended and causing someone else to get in an accident, I coasted to the shoulder where I calmed down then shut off the car and restarted it.

Here are my fault codes,
6 Faults Found:
01050 - Glow Plug Monitoring
35-10 - - - Intermittent---
00560 - Exhaust Gas Recirculation System
17-10 - Control Difference - Intermittent
00777 - Accelerator Position Sensor (G79)
27-10 - Implausible Signal - Intermittent
00527 - Intake Manifold Temperature Sensor (G72)
30-00 - Open or Short to B+
00539 - Fuel Temperature Sensor (G81)
30-00 - Open or Short to B+
00522 - Engine Coolant Temperature Sensor (G62)
30-00 - Open or Short to B+
=========================
the last time I checked the codes, the only fault was Glow plugs, due to no harness is installed. (In garage)
I also have a PD 150 intake with egr delete pipe. I am running RC 3 so this code maybe due to a different chip set that I was running for a couple of months.


So the code that stands out to me is the Accelerator sensor code. Which makes sense since the symptom matches the code.

Now to determine if something else may trigger the same symptoms and codes.
This is where I need help from the community. Should I replace the Throttle sensor, assuming it is a couple hundred and is readily available?

Or is more troubleshooting required?
This weekend will be the only "free" time I will have in the next 3 to 4 weeks so I need to spend my time wisely.

Any and all help would be appreciated.

Thanks.
 

ed mocz

Veteran Member
Joined
Mar 21, 2010
Location
Las Vegas NV
TDI
1997 Passat
I just went through the same thing. I replaced all the vacuum lines including the one inside the computer. Also, I cleaned the grounds near the battery. That took care of the problem. A quick search in this forum will give all the details.
 

OilBurnerDE

Veteran Member
Joined
May 6, 2003
Location
Newark, Delaware
TDI
1997 Passat T-Red
The line in the ecu was replaced recently, maybe in the past year or two, and was inspected when I replaced the chip set in August. I have experienced a different code when that was bad.

The ground issue sounds like the right course, as that would explain the other codes related to the "open to short" error.

I will continue to search but would appreciate more input as my time in front of a computer has been seriously hampered by work. I used to do all the valuable searching at work :) Not recently though. I am responsible for moving my company (networking and technology) to another building beginning next week. Preparing for the move and testing systems has severely hampered my TDI club time. ;-)

Thanks for the tips. Much appreciated! keep them coming!
 

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
With that many codes its power or ground related. Start by checking your fuses, then clean the battery terminals and then hit the various grounds. Check to see if the power wires all look fine on the back of the fuse panel.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, MA. USA
TDI
2015 GSW 6M in S trim the other oil burners: 1967 two stroke Sonett 1988 Bolens DGT1700 1962 Quantum III
There is a common engine wiring harness junction ground point (I think it's really just a fat solder joint with a bunch of wires involved) called "220". Many of the items you mention are among these. All except the EGR, which might be due to the RC3 tune.
"220" junction includes sensors G72 IAT sensor, F47 brake switch, G81, F60 closed throttle sensor, G62, G70, G28 rpm sensor, and some others.
The single wire into the ECU to which all these other sensor wires are soldered, is a brown with blue stripe, 1 mm cross section wire (versus .5 for most of the others to the ECU) and is connected to termination 33 of the 68 in the ECU.
The junction point, as I recall, is about 6 inches back from the ECU wiring harness plug.
Guess where I'd start...... I'll give you "220" guesses.
 

OilBurnerDE

Veteran Member
Joined
May 6, 2003
Location
Newark, Delaware
TDI
1997 Passat T-Red
Thanks for the help guys,

Lug I am having problems locating this junction port (sent you an IM) I don't see anything within 6 inches of the ecu wiring harness plug. I assumed you meant near the ECU and I don't see anything. So I guess I am looking in the wrong location.

I am in the process of cleaning the grounds. The main battery ground to body looked clean with little or no corrosion. The one next to it with the wiring harness grounds looked more corroded but not that bad. The battery to bell housing also was cleaned.

Regardless those are cleaned and I just need to put it back together now.

I hate electrical problems, because they can be intermittent. I have to feel confidence int the car, especially since this particular issue can be catastrophic due to the way it failed on my in high speed traffic.

I wish it was a failed part that I can see, at least I would then have confidence that the issue was fixed.

Thanks again.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, MA. USA
TDI
2015 GSW 6M in S trim the other oil burners: 1967 two stroke Sonett 1988 Bolens DGT1700 1962 Quantum III
The single wire into the ECU to which all these other sensor wires are soldered, is a brown with blue stripe, 1 mm cross section wire (versus .5 for most of the others to the ECU) and is connected to termination 33 of the 68 in the ECU.
The junction point, as I recall, is about 6 inches back from the ECU wiring harness plug.
Did you look about 6 inches inside the ECU wiring bundle?
My suspicion is that the problem is between that 220 junction inside the wiring bundle, and the pin connection #33 onto the ECU.
If it were just one sensor going bad I'd say before the 220. but with so many failing, and all of them sharing this brown with blue stripe wire, I really think this is where the problem is.
 

OilBurnerDE

Veteran Member
Joined
May 6, 2003
Location
Newark, Delaware
TDI
1997 Passat T-Red
No I did not look inside the wire bundle. I was looking for the wrong thing then. I was looking for something attached to the car body.

After I cleaned the four grounding points and installed my new glow plug harness. I took it out for about a half hour or so. No symptoms or codes. Tomorrow I will try to peel back the boot that surrounds the ecu wiring harness and look for this junction and see if I see any issues.

Thanks for the follow up explanation!
 

kzoc

Veteran Member
Joined
Sep 9, 2008
Location
Austin
TDI
97 A3 Jetta 1.9 TDI, and 6 Volvo's!
I, too, just went through this...

Cruisong in the car, going to S.A., hit the clutch to downshift, and had no throttle but the car was running (idling) fine. A3 Jetta TDI, BTW...

80 mile tow later, still the same code (P0121 IIRC). Thanks AAA RV!

Looked here on the forum, tried replacing the vacuum tubing with no success. Took the car to Robby at runonbeer.com, and he diagnosed the signal from the pedal actuator getting to the ECU. He suggested getting an updated ECU.

Talled to 1stVW parts, and they said there are 4 JB ecu's in the States, that they are an electrical part, and not eligible for return. And they cost $1366!!!

I promptly found a JB ecu here in the classifieds. Plugged it in, and the car is running fine once again. I suspect Robby tried cleaning the grounds since I now have to reset my radio code. But I'm verry happy with the seller of the ECU, and Robby.

Total cost was $140 for the ecu, and an hour of diagnosis.

HTH-
 

OilBurnerDE

Veteran Member
Joined
May 6, 2003
Location
Newark, Delaware
TDI
1997 Passat T-Red
Thanks Tom, That is basically what I saw before the rains came and I had to put it back together. Although I didn't get the boot pulled down all the way and I couldn't figure out how to get the harness "shroud" off and I didn't want to break it. Any trick to removing it?

Also once I get to the point that your picture shows, how do I know what to look for? I know very little about troubleshooting electrical things. and what I do know, I forget! :)

I did ask my wife to look at my brake lights but they were off and were coming on when I hit the pedal. I replaced the brake switch last year when it failed.

I drove it today without issues and reluctantly will be commuting with it tomorrow. If I don't have any problems I will continue driving it until I get a chance to get under the hood again.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, MA. USA
TDI
2015 GSW 6M in S trim the other oil burners: 1967 two stroke Sonett 1988 Bolens DGT1700 1962 Quantum III
There is (are) a small triangular tab on the side of the 68 pin housing shroud that slides over and catches behind an opposing tab located on the plug base. Maybe one pair of lock tabs on each side, maybe only one on one side, I don't remember.
Identify the tab(s), depress it (them) and the housing can be slid off the plug base.
 

bikeprof

Veteran Member
Joined
Sep 2, 2005
Location
Pagosa Springs, Colorado(YEAH!)
TDI
1996 Passat B4 Variant white, 1996 Town & Country 3.8 LXI
WOW! Thanks so much for this INFO! I will check and clean tomorrow, seems more pausible than a bad ECU like we diagnosed today with a VAG-COM.

Now I now ANOTHER place where them little gremlins hang out in these B4's!


There is a common engine wiring harness junction ground point (I think it's really just a fat solder joint with a bunch of wires involved) called "220". Many of the items you mention are among these. All except the EGR, which might be due to the RC3 tune.
"220" junction includes sensors G72 IAT sensor, F47 brake switch, G81, F60 closed throttle sensor, G62, G70, G28 rpm sensor, and some others.
The single wire into the ECU to which all these other sensor wires are soldered, is a brown with blue stripe, 1 mm cross section wire (versus .5 for most of the others to the ECU) and is connected to termination 33 of the 68 in the ECU.
The junction point, as I recall, is about 6 inches back from the ECU wiring harness plug.
Guess where I'd start...... I'll give you "220" guesses.
 
Top