Non-Trouble Code Procedures
1. Disconnect vacuum hose from servo and install a vacuum gauge in hose.2. Start engine and run at idle. Vacuum gauge should read 10 inches Hg.
3. Shut engine Off, vacuum should still read 10 inches Hg.
4. If vacuum is below 10 inches Hg, check for vacuum leaks in vacuum reservoir, vacuum hoses, check valve or poor engine performance.