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Test N - Key Power Check

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: Charging system overcharging. Battery charger connected with engine running. Jump starting vehicle.

  1. Turn key off and wait 10 seconds. Install breakout box and connect ECA. Set DVOM on 20-volt scale and connect to test pin 5 and 60. During KEY ON/ENGINE RUNNING (KOER) SELF-TEST, observe DVOM and record codes. If reading is above 17.5-volts, repair charging system for overcharging condition. If reading is below 17.5-volts and code 65 is displayed, replace ECA and repeat QUICK TEST . If reading is below 17.5-volts and code 65 is not displayed, go to next step.
  2. Continuous Code 65 Displayed. Perform KEY ON/ENGINE OFF SELF-TEST and record service codes. If continuous code 65 is displayed, check charging system for intermittent overcharging condition (above 17.5-volts). If code 65 is not displayed, fault cannot be duplicated at this time. Continuous code 65 testing is complete.
  3. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and connect ECA. Set DVOM on 20-volt scale. Measure voltage between test pin 5 and 60, and perform KOER SELF-TEST. If reading is above 7.5-volts and code 55 is displayed, replace ECA and repeat QUICK TEST . If reading is above 7.5-volts and code 55 is not displayed, go to step 5). If reading drops below 7.5 volts, go to next step.
  4. Turn key off. With breakout box installed and ECA connected, set DVOM on 200-ohm scale. Measure resistance between test pin 5 and key power terminal on EEC power relay. If reading is 5 ohms or less, check charging system for undercharging condition. If reading is more than 5 ohms, repair open in key power circuit and repeat QUICK TEST .
  5. Continuous Code 55 Displayed. Perform KEY ON/ENGINE OFF SELF-TEST and record service codes. If continuous code 55 is displayed, check charging system for intermittent overcharging condition (above 17.5-volts). If code 55 is not displayed, fault cannot be duplicated at this time. Continuous code 55 testing is complete.
Fig 1: Key Power Circuit
G2554