Est Emission System Check
NOTE:
When test terminal is grounded, the ignition timing will adjust to a fixed position. This will usually cause a timing adjustment that can be verified by a change in engine RPM.
- With engine operating at fast idle, note timing change as test terminal is grounded. System is operating properly if timing changes. If timing does not change, proceed to step 2).
- Disconnect park/neutral switch and recheck for timing change. If timing changes, problem is either an improperly adjusted or faulty park/neutral switch. If timing does not change, check for grounded wire from terminal "H" of ECM to park/neutral switch. If wire is not grounded, replace ECM.
NOTE:
See COMPUTERIZED ENGINE CONTROLS section for additional information.