Diagnostic Aids

If boost control system check has been performed and no electrical or vacuum related fault is noted, check for misadjusted or sticking by-pass valve actuator, or binding by-pass valve or linkage. An intermittent may be caused by a poor connection, rubbed-through wire insulation, or a wire broken inside insulation. Inspect PCM harness connector for backed-out terminals, improper mating, improperly formed or damaged terminals, poor terminal-to-wire connection and damaged harness. To check for intermittent, disconnect PCM and install DVOM to monitor voltage between boost control solenoid control circuit at PCM connector and ground. With ignition on, observe voltage while manipulating related connectors and wiring harness. If failure is induced, voltage display will change. This may indicate location of fault.