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Code 11: Idle Mixture Adjuster (IMA) (Civic Without Catalyst)

  1. Turn off ignition. Remove hazard fuse in main fuse box 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. Disconnect 3-wire connector at sensor. Measure resistance across Yellow/White and Green/White wires of sensor. If resistance is not 400-6000 ohms, replace sensor. Measure resistance across Yellow/White and Brown wires of sensor. If resistance is not 400-6000 ohms, replace sensor.
  3. If resistance values are within specification, turn ignition on. Measure voltage between Yellow/White (pos.) and Green/White (neg.) terminals of sensor harness. If voltage is not about 5 volts, go to step 5). If voltage is about 5 volts, turn ignition off. Connect system checker harness between ECU and ECU connector.
  4. Turn ignition on. Measure voltage between terminals B20 (pos.) and C12 (neg.). If voltage reading is not .5-4.5 volts, repair open or short in Brown wire between ECU terminal B20 and IMA sensor. If voltage is within specification, substitute a known good ECU. If condition is rectified, replace original ECU.
  5. Measure voltage between ground and Yellow/White wire of sensor harness. If voltage is now about 5 volts, repair open in Green/White wire between ECU terminal C12 and IMA sensor. If voltage is not about 5 volts, turn ignition off.
  6. Connect system checker harness between ECU and ECU connector. Turn ignition on. Measure voltage between terminals C13 (pos.) and C12 (neg.). If voltage is now about 5 volts, repair open in Yellow/White wire between ECU terminal C13 and IMA sensor.
  7. If voltage is not about 5 volts, substitute a known good ECU. If voltage reading is now correct, replace original ECU.
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