1983 Mercury LN7 Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Code 23 - Throttle Position Sensor Test

  1. Disconnect ISC solenoid and verify curb idle per emission decal. Adjust as necessary (except for No Start problems). With ECA connected, connect voltmeter to rear of ECA connector J1 pins 9 and 12.
  2. Repeat Quick Test while observing meter. If voltage is 0.5-1.3 volts during test, disconnect ECA connectors and inspect for corrosion and damage. Reconnect ECA and retest. If problem is still present, replace ECA. If voltage is not 0.5-1.3 volts proceed with test.
  3. With key on and ECA connected, measure voltage at ECA connector J1 pins 11 and 12. Voltage should be 4-6 volts. If not, proceed to reference voltage test.
  4. Disconnect Air Flow Meter harness connector. Disconnect ECA plug J1. Connect an ohmmeter between ground and pins 9, 11, and 12 of plug. No continuity should exist between ground and any pin. Connect ohmmeter to all combinations of the 3 pins. No open circuits should exist.
  5. If circuit does not perform as specified, disconnect harness from sensor and repeat test at sensor. If continuity to ground or an open circuit between pins still exists, replace sensor. If sensor performs as specified, check and repair wiring harness as needed.
Fig 1: Throttle Position Sensor Circuit Diagram
G179
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