Volkswagen Front Wheel Drive 1974-1989 Repair Guide

Catalytic Converter


Many models are equipped with catalytic converters located in the exhaust system. This device contains noble metals acting as catalysts to convert hydrocarbons and carbon monoxide into harmless water and carbon dioxide. On earlier models, a warning light on the dash will glow STEADILY when inspection of the converter is required. Once the converter is inspected, the warning light can be be reset.

Many models are also equipped with a converter heat sensor. On models so equipped, damage and overheating of the catalytic converter, is indicated by a FLICKERING warning light. Damage or overheating can be caused by the following:

Engine misfire
Improper ignition timing
Incorrect fuel mixture
Faulty air pump diverter valve
Faulty temperature sensor
Engine under strain caused by trailer hauling, high speed driving in hot weather, etc

A faulty converter can be indicated by one of the following symptoms:

Poor engine performance
The engine stalls
Rattling in the exhaust system
A high CO reading at the tail pipe

Never attempt to remove the converter from a just-run or warm engine. Catalytic temperatures can reach 1,900°F (1,038°C), be careful!


Do not drop or strike the converter assembly or damage to the ceramic insert will result.

Check the converter as follows:

  1. If equipped, disconnect the temperature sensor from the converter.
  3. Loosen and remove the bolts holding the converter to the exhaust system and the chassis.
  5. Remove the converter.
  7. Hold the converter up to a strong light and look through both ends, checking for blockages. If the converter is blocked, replace it.