Ground Circuits
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1992 Volkswagen Passat, 1992 Volkswagen Jetta, 1992 Volkswagen Golf, 1992 Volkswagen GTI, and 1992 Volkswagen Fox. However, it is still accessible from the selected car via links, so may be relevant.
Using Multimeter (US 1119), check resistance of ground circuits for ECU. Remove ECU connector. Check continuity to ground on terminals No. 2 and No. 9. See Figure . Resistance should be zero ohms. If resistance is not zero ohms, repair open or short in wiring.