Toyota Corolla (E120): Malfunction in tachometer

Wiring diagram

Inspection procedure

Inspection procedure

  1. Check output value of ecm.
  1.  Connect the hand–held tester to dlc3.
  2. Turn the ignition switch to on and push the hand–held tester main switch on.
  3.  Select the data list mode on the hand–held tester.

2 Inspect combination meter assy

2 Inspect combination meter assy

(Reference) inspection using oscilloscope

(Reference) inspection using oscilloscope

  1.  check the input signal waveform.
  1.  Remove the combination meter assy with connectors still connected.
  2.  Connect the oscilloscope to the terminals c9–19 of combination meter assy and body ground.
  3.  Start engine.
  4.  Check the signal waveform.

3 Check harness and connector(between ecm and combination

3 Check harness and connector(between ecm and combination meter assy)

  1. Remove the combination meter.
  2.  check the continuity between terminals 5 (tach) of ecm and c9–19 of combination meter connector.

Standard: there is continuity.

Check and replace ecm

Check and replace ecm

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    Circuit description
    In the diagram below, when the engine is cranked, current flows from terminal st2 of the ignition switch to the starter relay coil and also current flows to terminal sta of the ecm (sta signal). When the sta signal and ne signal are input to the ecm, tr is turned on, current flows to the c ...

    On–vehicle inspection
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