Pressure Regulator Control Solenoid Valve
- Pressure regulator control solenoid valve is located in control box on firewall. See Figure . Warm engine to operating temperature. Disconnect vacuum hose No. 1 from pressure regulator. Connect vacuum gauge to hose. If manifold vacuum is present, go to step 3. If manifold vacuum is not present, go to next step.
- Unplug 4-pin connector from control box on firewall. See Figure . If manifold vacuum is now present, repair shorted Light Green wire between ECM terminal A19 and control box connector. If wire is okay, substitute a known-good ECM. If vacuum is not present, check vacuum hoses No. 1 and 3 for leaks or obstructions. If hoses are okay, replace pressure regulator control solenoid valve.
- Turn ignition off. Unplug 4-pin connector from control box. Using a fused jumper wire, connect positive battery terminal to terminal "C" (Black/Yellow wire) of cut-off solenoid valve side of connector. Connect negative battery terminal to terminal "D" (Light Green wire) of cut-off solenoid valve side of connector. Start and idle engine. If manifold vacuum is now present, replace cut-off solenoid valve.
- If manifold vacuum is not present, measure voltage between Black/Yellow (positive) wire and ground. If battery voltage does not exist, repair open in Black/Yellow wire between fuse No. 22 and solenoid valve connector. Reconnect wire harness to solenoid valve.
- Connect test harness between ECM and vehicle harness. Start engine. Connect jumper wire from terminal A19 to ground. If manifold vacuum is not present, cut-off solenoid valve is okay. If vacuum is present, repair open in Light Green wire between ECM and solenoid valve connector.