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Code 20 - Load Detector

  1. Turn ignition off and remove hazard fuse at battery positive terminal for 10 seconds to reset ECU. Start engine and observe "CHECK ENGINE" light. If light is off, problem is intermittent. Test drive and check again.
  2. If light is on, turn ignition off. Open lid of main fuse panel in engine compartment. Disconnect 3-wire electric load detector connector. Turn ignition on. Measure voltage between Black/Yellow and Black wires. If battery voltage is present, go to step 4). If battery voltage is not present, go to step 3).
  3. Measure voltage between Black/Yellow wire and ground. If battery voltage is present, repair open in Black wire between the connector and ground. If battery voltage is not present, repair open in Black/Yellow wire between No. 4 fuse and 3-wire connector.
  4. Turn ignition off. Connect ECU test harness between ECU and ECU connector. Disconnect connector "B" from ECU side only. Connect Green/Red wire terminal of electrical load detector connector to ground. Check for continuity between ECU terminal B19 and ground. See Figure . If continuity does not exist, repair open Green/Red wire between ECU connector terminal B19 and load detector connector.
  5. Reconnect connector "B" to ECU. Turn ignition on. Measure voltage between Green/Red (pos.) and Black (neg.) 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 connector "B" from ECU main wire harness side.
  6. Turn ignition on. Measure voltage between ECU terminals B19 (pos.) and A18 (neg.). If 4.5-5 volts is present, repair short in Green/Red wire between ECU terminal B19 and 3-wire electric load detector connector. If voltage is not present, substitute a known good ECU and recheck. If specified voltage is now available, replace original ECU.
  7. Turn ignition off. Reconnect load detector connector. Turn ignition on. Measure voltage between ECU terminals B19 (pos.) and A18 (neg.) 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 rectified, replace original ECU.
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