Electromagnetic Interference (EMI) & Electrical Noise
WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
Some electrical components or circuits are sensitive to Electromagnetic Interference (EMI) or other types of electrical noise. Perform the following procedures:
- A misrouted harness that is too close to high voltage/high current devices such as secondary ignition components, motors, generator, etc. These components may induce electrical noise on a circuit that could interfere with normal circuit operation.
- Electrical system interference caused by a malfunctioning relay, PCM driven solenoid, or switch. These conditions cause a sharp electrical surge. Normally, the problem will occur when the malfunctioning component is operating.
- Improper installation of non-factory (aftermarket) add-on accessories such as lights, 2-way radios, amplifiers, electric motors, etc. These accessories may lead to an emission related OBD II failure while in use, but do not fail when the accessories are not in use.
- Test for an open diode across the A/C compressor clutch, and for other open diodes.
- Test the generator for a bad rectifier bridge that may be allowing AC noise into the electrical system.