80 L5-2309cc 2.3L SOHC (NG) (1991)
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CAUTION: Direct contact with meter probes at the connector terminals can easily damage the small contacts, causing poor connections and
risking future intermittent faults.
Audi Special Tools include adapters for making test connections safely and preventing connector damage. See: Tools and Equipment
Continuity (approximately 0 Ohms): Little or no resistance indicates that there is a continuous conductive path between the two test points. In
the example, this indicates that the normally-open full-throttle switch is faulty.
NO Continuity: There is no connection-an open circuit. As shown, this is correct for the normally-open full-throttle switch. Also check that the
switch closes, completing the circuit, when actuated by the fully-open throttle.
Voltage Drop
Checking voltage drop across connections or components as shown will indicate whether there is abnormal resistance creating an additional load
in the circuit-consuming power and dropping the voltage available to other parts of the circuit.
NOTE: Voltage drop measurements can only be made when the circuit is powered and there is normal current flow.
The example illustrates troubleshooting the back-up light switch. The switch is in the circuit to switch power to the back-up lights On and Off.
When Reverse gear is selected and the switch is closed, it should have very little resistance and not be a consumer.
If dirt or corrosion on the switch contacts creates resistance, some of the available battery voltage goes into overcoming that resistance. Less
voltage is available to light the back-up lights, and they will not be as bright.
NOTE: An ohmmeter can measure resistance (or check continuity) only when the circuit is not powered, i.e. when there is almost no load.
CAUTION: Direct contact with meter probes at the connector terminals can easily damage the small contacts, causing poor connections and
risking future intermittent faults.
Audi Special Tools include adapters for making test connections safely and preventing connector damage. See: Tools and Equipment