VW Vanagon Accessories
Bike rack, ladder, spare tire carrier, gas can carrier, jack carrier

Information and orders:

Gary Lee - Calgary, Alberta, Canada (403) 272-7284
Email gary2a@telus.net

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VW Factory Air Flow Meter Service Harness
"Vanagon Intermittent syndrome"

VW technical service bulletin reads as follows:

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Technical Bulletin Group: 24 Number: 92-01 Date: February 29, 1992 Subject: Vanagon Intermittent Misfire Model(s): All Vanagon Digifant Fuel Injection Engines CONDITION After driving for 1/2 to 2 hours at a constant speed, vehicle experiences lack of power, cuts-out or stalls, often accompanied by bucking or jerking of the vehicle. In ALL cases, the vehicle will restart immediately. This symptom may not re-occur for several weeks/months. Inspection by the dealer results in nothing conclusive. Some air-flow meters may experience a vibration resonance of the metering potentiometer wiper during extended constant driving. This resonance causes the air-flow meter to supply an intermittent signal to the Digifant ECU. The ECU will then default to a "no-load" condition and reduce the injection time. SERVICE Harness, Part No. 025 906 302, is available to resolve this condition. * remove electrical connector from air flow sensor (see Figure 24-174) * install converter assembly, Part No. 025 906 302, between harness and air flow sensor NOTE If customer complaints persist after performing the above repair, contact your Zone Product Support Specialist (TSM in Canada)

Technical Bulletin Group: 24 Number: 92-02 Date: April 30, 1992 Subject: Vanagon Drivability Complaints Model(s): All Water Cooled Engine Vanagons SUPERCEDES TECHNICAL BULLETIN 24-92-01 (February 29, 1992) CONDITION After driving for an extended period of time at a constant speed, the vehicle may, on occasion, experience a deterioration of performance which may be accompanied by a hesitation or surging. In many cases, after turning off the engine and subsequent re-start or without having taken any action, the symptoms disappear. These symptoms may not recur for several weeks or months. SERVICE To resolve this condition, wire harness Part No. 025 906 302, should be installed. This harness provides improved signal voltage stabilization. * remove electrical connector from air flow sensor * install wire harness, Part No. 025 906 302, between main harness connection and air flow sensor connection.

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The VW factory harness which addresses this problem costs about $160.00.  Some people report success with a less costly solution.  Solder a 15 to 25 volt  22 MFD tantalum capacitor between terminals 2 and 4 of your AFM.  Two capacitors connected in parallel will double the capacitance (10+10=20). The capacitor can be installed inside the AFM or at the AFM connector on the outside.  Peel back the rubber boot covering the connector to gain access to the terminals.  The positive terminal of the capacitor is soldered to terminal 2, negative to 4.  The terminal numbers are stamped on the connector by the Air Flow Meter.  The capacitor costs about $0.50 to $2.00 and can be purchased from Radio Shack or an electronic component supply store. 
It should be noted that the capacitor or harness 'fix' will only address symptoms which are as described in the above Technical Bulletins.  Many people have tried the capacitor with no success.  Upon close evaluation,  their symptoms were not exactly as described above. 
In other words, there are other intermittent problems which are caused by  plugged fuel filters, bad grounds, bad O2 sensors, ECU problems, ECU power supply problems etc. etc.

It looks like the VW solution is an active device.  The chip appears to be a Phillips low voltage op-amp
see http://www.semiconductors.philips.com/pip/SA5230.html

Below are some pictures of a VW 025 906 302 factory service harness to address the so-called "Vanagon Syndrome"

I do not have this harness available for sale.   I just put up this web page in case anybody was interested in seeing what the harness looks like..

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