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ESC Controller Equipped Models

  1. Connect tachometer to engine. Block DRIVE wheels. FIRMLY apply parking brake. Place transmission in Park or Neutral. Run engine at fast idle (about 1500 RPM). With engine at normal operating temperature, tap engine block in area of detonation sensor. If RPM drops, system is operating properly.
  2. If RPM does not drop, disconnect harness from ESC controller (located in engine compartment) and check for RPM change. If there is no change in RPM, proceed to step 5). If RPM drops, run engine at 2000 RPM. Connect a digital voltmeter between disconnected ESC harness connector terminals "E" and "D". Voltage should not exceed .08 volt on the AC scale.
  3. If voltage reading is correct, problem is a faulty ESC connection or ESC controller. If voltage is not correct, check for an open in wire from ESC controller connector terminal "D" to ground.
  4. Repair wire if an open is found. If no open wire is found, check for an open or poor connection between detonation sensor and ESC controller connector terminal "E". If circuit is okay, replace detonation sensor.
  5. Inspect "SERVICE ENGINE SOON" light. If light is on, problem is a faulty ESC controller or detonation sensor, proceed to step 7). If light is off, turn ignition switch to "ON" position (engine not running) and check voltage from ground to ESC terminal "C".
  6. If voltage is less than 2 volts, replace ECM. If voltage is greater than 2 volts, repair short to voltage in wire from ESC terminal "C" to ECM knock signal terminal.
  7. If light was on in step 5), reconnect ESC controller. With engine idling, disconnect knock sensor. Note timing change.
  8. If timing increases, check for source of engine knock. If knock is not present, replace knock sensor. If timing did not increase in step 7), disconnect terminal "E" from controller connector and once again note timing change.
  9. If timing does not increase in step 8), replace ESC controller. If timing did increase, circuit to knock sensor is picking up induced signals. Move sensor signal wire away from other electrical circuits (i.e. spark plug or alternator wiring).
    NOTE: If Code 43 is set in ECM memory, see appropriate CODE 43 chart in the appropriate CEC TESTS W/CODES article in the ENGINE PERFORMANCE section. Refer to the following list.
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