3B ECU pin 54

[Mike Sylvester]

The coding plug is meant to tell the ECU about the application options.
e.g. in the urs4 one of the pins if grounded, tells the ECU to limit the
speed to 130mph.

I would think that all of the pins are internally pulled up to a +
voltage with a resistor and to enable a certain option the pin is
connected to ground in the wiring harness.

I just need to know, is pin 54 grounded in the wiring harness in the '91
200q?
Pin 2 is also part of the coding plug and is grounded in the '91 200q.

Mike

www.urq20v.com

> -------- Original Message --------
> Subject: Re: 3B ECU pin 54
> From: Bernie Benz <b.benz at charter.net>
> Date: Sun, February 28, 2010 10:57 am
> To: "Mike Sylvester" <mike at urq20v.com>
> Cc: 200q20V mailing list <200q20v at audifans.com>
> 
> 
> Scott, SJM Auto-Technik identifies ECU pins 38, 39, and 54 as “Coding  
> plug”. Must be a ground connection for a coding device to the ECU  
> ground. Is it connected within the ECU to 10, 14, and 24?
> 
> Bernie
> 
> 
> On Feb 27, 2010, at 12:47 PM, Mike Sylvester wrote:
> 
> > The Bentley sect. 28.44 states that the 3B ECU pin 54 is ground.
> > The wiring diagram page 541 current track 43 shows it going to  
> > connector
> > T6f pin 3.
> > It doesn't appear that this is pin is connected to anything on the  
> > other
> > half of the connector.
> >
> > I think T6f is the software coding plug.
> >
> > I measured this pin on my car, with the ECU connector removed, and  
> > it is
> > not connected to ground.
> >
> > Can anyone tell me if it is grounded on your car?
> >
> > I'm trying to debug some running issues.
> >
> > 1.)  Occasional hard misfire at very light throttle.
> > 2.)  erratic acceleration and low boost.
> >
> > I've already verified the following sensors and wiring:
> >
> > MFTS
> > intake air temp
> > engine speed sensor
> > timing reference sensor
> > Altitude sensor
> > coolant temp sensor
> > Ground connections at ECU pins 10,14,24
> >
> > I ran the ECU output test and everything clicks as it should.
> >
> > I'm running out of things to check.
> >
> > Mike
> >
> > www.urq20v.com
> >
> >
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