Analyzing PCM Data

Once fault area is identified, circuit must be checked to determine if wiring or component is at fault. When making circuit and component measurements, make sure all accessories, as well as dome, trunk and hood lights are off. Use any of the following methods to diagnose a suspected PCM wire circuit or device. Some methods are specific to a certain type of PCM device:

• Click testing solenoids and relays in OUTPUT TEST MODE. See CLICK TESTING SOLENOIDS & RELAYS .
• Harness opens and harness shorts. See CHANGING INPUT & VERIFYING OUTPUT RESPONSE .
• Solenoids and relays coil resistance. See PERIPHERAL INPUTS .