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Electronic Spark Control System

  1. Connect tachometer to terminal "D" of ignition module. Place transmission in "P" or "N". Start engine. Run at approximately 1800 RPM. Tap engine block in area of knock sensor and check for RPM drop.
  2. If RPM drops, system is OK. If no RPM drop, unplug the ESC module and check for RPM drop. If there is no RPM drop, go to step 6.
  3. If RPM drops, run engine at 2000 RPM and check voltage between pins "E" and "D" with digital voltmeter. There should be over 80 millivolts (.080 volts) at 2000 RPM. See Figure.
  4. If voltage correct, check for faulty ESC connection or ESC module. If voltage not correct, check for open in ground circuit. Ground is BLK/WHT wire at terminal "D" of ESC module.
  5. If ground circuit is OK, check for faulty connection from knock sensor to module. If circuit is OK, replace knock sensor.
  6. If there was no RPM drop when ESC module was disconnected in step 2), check engine light. If light is off, turn engine off and turn ignition "ON". Check if there is 2 volts present at ESC harness terminal "C".
  7. If there is less than 2 volts, replace ECM. If over 2 volts, correct short on YEL/BLK wire from ESC terminal "C" to ECM terminal "B7".
  8. If engine light was on in step 6, plug in ESC module and run engine at 1500 RPM. Check timing. Unplug knock sensor and check for timing change. If timing changed, replace knock sensor.
  9. If timing did not change in step 8, remove terminal "E" from ESC module connector with engine at 1500 RPM. Check timing. If no change, check for faulty ESC connection or module.
  10. If timing changed, knock sensor-to-ESC module wire may be routed too close to ignition wires and picking up false knock signals.
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