With PCM

Intake Manifold Tuning Valve Diagnosis:

CIRCUIT DESCRIPTION
The tuning valve is activated through a relay by the Powertrain Control Module (PCM) during periods of acceleration where engine RPM is over 3000 and throttle position is over 34%.

The tuning valve relay is powered by ignition voltage and is turned "ON" and "OFF" when the PCM grounds the tuning valve control circuit. When the relay is activated, it applies ignition voltage to the tuning valve.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This step determines if the system is functioning at the present time.
2. By cycling the tuning valve "ON" and "OFF" will determine if the tuning valve relay is operating.
3. This will determine if the tuning valve relay has ignition voltage at tuning valve relay connector, terminal 30.
4. This will determine if the tuning valve relay has ignition voltage at the tuning valve relay connector 86.
5. This step will determine if the relay related wiring to valve or the tuning valve is at fault.
6. This step will determine if the PCM, tuning valve relay or related wiring is at fault.

DIAGNOSTIC AIDS
Throttle Position (TP) Sensor - An intermittent TP sensor output will cause the PCM to receive a false input.