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Home >> Honda >> 1990 >> Civic Base, 2D Hatchback >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 1.5L TBI >> Trouble Code Tests - PGM-FI >> Code 20 - Electric Load Detector

Code 20 - Electric Load Detector

  1. Turn ignition off. Remove HAZARD fuse in main fuse panel for 10 seconds to reset ECU. Start engine and with engine at idle, turn on headlights. Verify if CHECK ENGINE light is on and if LED is flashing Code 20. If LED is flashing Code 20, go to next step. If LED is not flashing Code 20, problem is intermittent. Check for poor connectors or loose wires.
  2. Turn ignition off. Open lid of main fuse panel in engine compartment. Disconnect 3-wire electrical load detector. Turn ignition on. Measure voltage between Black/Yellow (positive) and Black (negative) wire terminals of harness. If battery voltage is present, go to step 4).
  3. If battery voltage is not present, measure voltage between Black/Yellow wire and ground. If battery voltage is now present, repair open in Black wire between connector and ground. If battery voltage is not present, repair open Black/Yellow wire between No. 14 fuse and connector.
  4. Turn ignition off. Connect ECU Test Harness between ECU and ECU connector. See Figure . Disconnect connector "B" from ECU side only. Connect Green/Red terminal of load detector harness connector to ground. Check for continuity between ECU terminal B19 and ground. If continuity does not exist, repair open Green/Red wire between ECU connector terminal B19 and load detector connector.
  5. If continuity did exist, disconnect Green/Red terminal of 3-wire connector on models. Reconnect connector "B" to ECU. Turn ignition on. Measure voltage between Green/Red (positive) and Black (negative) terminals of load detector harness. If 4.5-5 volts is present, go to step 7). If 4.5-5 volts is not present, disconnect "B" connector from main wiring harness, not ECU. Measure voltage between positive terminals A18.
  6. If voltage is now 4.5-5 volts, repair short in Green/Red wire between ECU terminal B19 and load detector connector. If voltage is not 4.5-5 volts, substitute a known good ECU. If correct voltage is now available, replace original ECU.
  7. Reconnect load detector connector. Start engine. Measure voltage between positive terminals B19 and negative terminal A18 under the following conditions.
    • Headlight switch in first position - Voltage should be 2.5-3.5 volts.
    • Headlight switch in second position - Voltage should be 1.5-2.5 volts.
  8. If voltage is not as noted, replace faulty electrical load detector. If voltage responds as indicated, substitute a known good ECU. If condition is corrected, replace original ECU.
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