ECU wiring changes in the harness for 1988 and Newer Vanagons

[r.e.wing_fc3s]

Original Thread Title:
Items/service info unique to late california vanagons

in ETKA a "check engine light" for the vanagon is clearly shown. it goes in the blank space next to fog light/hazard/defrost switch. i googled around and read this was for the late model california vanagons. Did these vans have a "better" ecu or was if just capable of storing dtc's? Is there a california only pro-training that details how to check the codes and were the diagnostic port was?

[kamzcab86]

Your post intrigued me, so I did a brief bit of research too. I found this on Wikipedia:

"In North America, Volkswagen released two other versions of the Digifant fuel injection system (in addition to standard Digifant II described above).

A limited number of 1987-1990 California Golf and Jetta models are equipped with Digifant II that features an on-board diagnostics system (OBD). These vehicles have 'blink code' capacity to store up to five Diagnostic Trouble Codes (DTCs). Diagnostic troubleshooting is done by pressing the Check Engine switch on the dashboard. This system can also have carbon monoxide (CO), ignition timing and idle speed adjusted to baseline values.

In 1991, California Golf, Jetta, Fox, Cabriolet and Corrado vehicles were equipped with expanded OBD capabilities. This version was re-named "Digifant I". These later Digifant versions have 38-pin ECMs with Rapid Data Transfer and permanent DTC memory. All Eurovans with Digifant also have rapid data transfer and permanent DTC memory. These systems use a throttle plate potentiometer to track throttle plate position in place of the idle and full throttle switches used on earlier systems.

Another characteristic of Digifant II equipped vehicles in California is a switch mount on the dashboard which has a "Check Engine" symbol. Digifant I models in California feature a Check Engine light, with the display of codes done by a special Volkswagen tool under the shift boot, or by a jumper and an LED by the home mechanic."

A couple of interesting things: 1) My 1990 California Vanagon has no Check Engine Light switch (or light). 2) I have never, ever come across a Digifant Cabriolet with a Check Engine Light switch. The only California Cabriolets with a Check Engine Light (non-switch version) and are, thus, OBD I are those with Digifant I (indicated, also, by the VIN: 5th digit is a C).

Odd, very odd...
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~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
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"Real knowledge is to know the extent of one's ignorance." - 孔子

[r.e.wing_fc3s]

indeed. i read that same page on wikipedia.

heres an excerpt from http://vanagonparts.com/digifant.html

Self-Diagnostic System

O2 Sensor Warning Light

All vehicles are equipped with an O2 sensor warning light, located on the instrument panel. The light illuminates when a mileage counter reaches 60,000 miles (90,000 miles on Vanagon) indicating recommended O2 sensor replacement and mileage counter reset.

Check Engine Light

California vehicles are equipped with a CHECK engine light and rocker switch on the instrument panel. The light illuminates when the ignition switch is turned to the ON position (for bulb check) and when engine management systems malfunction during normal engine operation.

[crazyvwvanman]

For sure VW was planning to add the check engine light and switch to display blink codes to Vanagons but as best I can tell they never did. My California 1988 Vanagon came with an owner's manual that shows the check light and code display switch on the dash cluster but the van itself did not have them.

The 022D versions of the Vanagon 2.1 ECU * DO STORE CODES! They can be displayed too. The extra wires are there in the ECU harness and the vehicle harness. The wires, light, and switch are shown in the 88/89 wiring diagrams in the Bentley.

Mark

[syncrodoka]

Neither my '90 or '91 CA vans have a CEL.
I don't see a CEL anywhere in your illustration.

[madspaniard]

[crazyvwvanman]

The 1988 Owners Manual shows the switch on page 40.

ECS-malfunction display switch

It explains what it is and says the various codes can be called up by the switch. It says "for further explanation of the codes and repair procedures see your VW dealer".

VW parts data shows it beginning in 1988, gives a part number 251906257 for the switch, and says "switch for catalyst control", "California".

My 88 manual has it but my 88 van did not. My 88 was bought new in San Diego.

Mark

[r.e.wing_fc3s]

[syncrodoka]

[r.e.wing_fc3s]

[r.e.wing_fc3s]

[r.e.wing_fc3s]

if you click on the link and zoom in its pretty clear. its the top one in the vertical row of switches.
_________________
Reference Automotive: NW Washingtons Vanagon Specialist. (360)366-6965. referenceautomotive.com

[syncrodoka]

As crazyvwvanman said they call that a "switch for catalyst control"

My '90/'91 owners manual shows the top position for the emergency switch, the middle position for the rear defroster and the lowest position for additional switch. There is no mention of a catalyst switch, CEL switch or any other switch.

[djkeev]

I've changed the title of this thread for I don't believe the 1988 - 91 wiring changes to be California specific.

Here are the Bentley wiring diagrams for 88 - 89 Vanagon USA

There is a newer thread where someone who says he has an 87 was asking about his ECU plug being different than that shown in the Bentley, it had more terminals.

I personally believe that he has an 88 titled as an 87.

https://www.thesamba.com/vw/forum/viewtopic.php?t=685324

It turns out that the difference between an 87 ECU plug and an 88 ECU plug is the addition of connectors for terminals 20 and 23. (See the wiring diagram below, Digifant Control Unit, current tracks 18 & 23)

Why are these connectors here?
What do they affect in the daily operation of the fuel injection system?

I searched, I Googled, I emailed people who SHOULD know such answers, but alas, no good answers. I recieved an email from a well known and respected supplier rebuilder who says that they don't know what the extra terminals do and they feel that they make no difference......... until I stumbled upon this old thread here on thesamba.

Rather than start a new thread, I figured to give rebirth this one.
The main posters on this thread are still active and have hopefully learned more about their units during the past six years.

The question seems to be, did VW wire these units for a self diagnosis of the fuel injection system? A CEL.

It appears that they did, but are the wires really installed in the vehicle?

It is obvious from this photo that they exist in the fuel injection harness.....

[/quote]

So the question is, do they also follow through to the dash and to the fuel injection relay as shown in the diagram? Current path 23 - 36.
And if it does, do 1988 units have that BK/W (23) wire on the terminal 4/86 ?

Is there a single GY/W wire using single connector 1n & 1m in the connection box to run to the dash?

If you pull the dash cluster, is there an unused three wire plug with GY/W, BK and BR wires in it?
Is the BK wire energized with the key on for it is shown to pull power from feed path #15 on current path 11?

The dash switch shown is a manually operated rocker switch with a light.

Who owns an 88 or newer unit and has the interest to do some investigating?

Curiously, Bus Depot shows that rocker switch as being available via special order for $20.

Dave
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Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[crazyvwvanman]

It seems like we cover this every couple years. Yes, impending California emissions rules were forcing the implementation of OBD by car makers, ahead of the Federal requirement for it. VW worked on adding it to the Vanagon but Calif delayed the requirement and VW didn't have to roll it out. But they came pretty close. Here is a page from the owner's manual, showing the ECS Malfunction light and switch on the dash that the extra pins on the ECU were supposed to connect to. 1988 Owner's Manual. The later version of the Vanagon Digifant ECU has OBD, yes it works and stored codes, VW# ending in 022D on ecu.

https://www.thesamba.com/vw/gallery/pix/1273390.jpg

Mark

[djkeev]

Mark, great information! ...... but I wonder, does your Van have the wires behind the cluster?

Dave
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Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[crazyvwvanman]

The grey/white wire is there on many vans, from dash to engine wiring box. I'm told it was there anyway for use in other markets for some rear lighting option. I don't recall an extra black hanging in the dash harness but who knows. I've sold my 88 and 89 vans.

The Bentley diagrams give the impression that various wiring changes occurred on exact model year breaks but experience shows otherwise.

As for the FI harnesses, I think there are at least 5 versions of the 2.1 Digifant harness. AFAIK the latest seem to have done away with the extra OBD pins.

Mark

[kamzcab86]

[emc]

In case the info is of any use - I have an 89 syncro made in SA and that GREY/WHITE cable (related to the ECS circuit in the bentley) goes all the way to the Right-hand tail-light plug to feed the inner bulb slot, which is blank so has never been used. I guess was for a rear fog light option. I'm currently looking for where it comes out under the dash as I will use the cable for a CEL for the LINK ecu that I am wiring into the van for a sub2.5L conversion.

[DrDarby]

I just found this thread. I have a very early 9/89 (1990) Vanagon. Door jamb sticker indicates FEDERAL doesn't mention California. Carfax shows this to be originally a VWoA Demo out of Utah.
Anyway I had the dash out to replace the blower motor and bypass the blower resistor with a variable electronic motor controller and upon reassembly noticed there was an extra plug in the dash harness I don't remember un-plugging from anything. It has the Gray / White, Black and Brown wires. I combed the Bentley and found the Emissions OBD switch under 1988 /1989 matched the colors.
I worked for VW during that time and never saw a Vanagon w/the OBDI switch however I did see a Jetta and a Cabriolet both California spec cars with the OBDI switch / light in the dash around 1990 or 91. I'm going to trace the gray/white wire and see where it goes. The black wire is in fact hot off of circuit 15 (key on).
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