Skylark V6-3100 3.1L VIN M SFI (1996)
Powertrain Control Module: Diagnostic Aids
Ohmmeter
An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO
resistance means good continuity.
Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher
impedance digital multimeter (J 39200).
When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVM's
apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading.
Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement,
take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement.
