Electronic Spark Advance (ESA) Control System

SYSTEM INSPECTION
1. Turn off following loads.
- Power steering
- A/C




2. Connect the timing light to the ignition timing checking harness with the arrow on its clamp facing the connector.




3. Connect the Special Service Tool (system selector) to the data link connector.
4. Set switch A to position 1.
5. Set the test switch to SELF TEST.




6. Start the engine and verify that the ignition timing retards as the engine warms up.
7. If not as specified, check the ECM terminal 3Q (Engine coolant temperature sensor) voltage.
8. Disconnect the Special Service Tool (system selector).
9. Verify that the engine is completely warmed up.




10. Increase the engine speed and verify that the ignition advances accordingly.
11. If not as specified, check voltage at following terminals.
- ECM terminal 3E (Mass air flow sensor)
- ECM terminal 4AH, and 4AL (Crankshaft position sensor)