Circuit Test B - Vehicle Battery
To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: battery cables and ground straps, voltage regulator and alternator, and ignition switch.
- Turn key on, leaving engine off. Set DVOM on 20-volt scale and measure voltage across battery terminals. If reading is less than 10.5 volts, service or replace discharged battery. If reading is 10.5 volts or higher, go to next step.
- Turn key on, leaving engine off. With ECA connected, set DVOM on 20-volt scale and measure voltage between battery negative post and signal return circuit in SELF-TEST connector. If reading is less than 0.5 volts, go to step 6). If reading is 0.5 volts or higher, go to next step.
- With breakout box installed and ECA connected, turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between battery negative post and test pins No. 40 and 60. If either reading is 0.5 volts or higher, repair ground circuit having a resistance higher than 0.5 volts and repeat QUICK TEST . If both readings are less than 0.5 volts, go to next step.
- With breakout box installed and ECA connected, turn key off and wait 10 seconds. Set DVOM on 200 ohm scale. Measure resistance between test pin No. 46 and test pins No. 40 and 60. If either reading is 5 ohms or higher, disconnect ECA connector and inspect for corrosion or damage. Repair wiring and recheck resistance. If reading is still too high, replace ECA and repeat QUICK TEST . If both readings are less than 5 ohms, go to next step.
- With breakout box installed and ECA connected, turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 46 and signal return circuit at SELF-TEST connector. If reading is less than 5 ohms, system is okay, repeat QUICK TEST . If reading is 5 ohms or higher, repair cause of excessive resistance in signal return circuit, then repeat QUICK TEST .
- Turn key on, leaving engine off. With ECA connected, set DVOM on 20-volt scale. Measure voltage between battery negative post and Keep Alive Power (KAPWR) circuit at EEC power relay. If reading is less than 10.5 volts, check KAPWR and Vehicle Power (V Power) circuits for shorts to ground. Also check KAPWR circuit from EEC power relay to battery positive post for open circuit. If reading is 10.5 volts or higher, go to next step.
- Turn key on, leaving engine off. With ECA connected, set DVOM on 20-volt scale. Measure voltage between battery negative post and ignition circuit at EEC power relay. If readings is less than 10.5 volts, check for open ignition switch circuits. Repair wiring and repeat QUICK TEST . If reading is 10.5 volts or higher, go to next step.
- Turn key on, leaving engine off. With ECA connected, set DVOM on 20-volt scale. Measure voltage between battery negative post and ground circuit at EEC power relay. If reading is 0.5 volts or higher, repair open circuit or short to ground in ground circuit and repeat QUICK TEST . If you entered this test for a code 78 and if reading is less than 0.5 volts, go to step 10). If you entered this test for any other code and if reading is less than 0.5 volts, go to next step.
- Turn key on, leaving engine off. With ECA connected, set DVOM on 20-volt scale. Measure voltage between battery negative post and vehicle power circuit at EEC power relay. If reading is less than 10.5 volts, replace EEC power relay and repeat QUICK TEST . If reading is 10.5 volts or higher, repair short to ground or open in vehicle power circuit from EEC power relay to test pins No. 37 and 57. Repeat QUICK TEST .
- Turn key on, leaving engine off. Connect VOM or STAR tester to SELF-TEST connector. With SELF-TEST deactivated, enter into CONTINUOUS MONITOR (WIGGLE) TEST . Observe VOM or STAR tester LED for indication of fault while bending and twisting harness from EEC power relay to ECA. If code 78 is displayed or if fault is indicated, isolate fault in vehicle power circuit, and repair as necessary. If code 78 is not displayed or if fault is not indicated, inspect EEC power relay and connectors for damaged pins, corrosion, etc. If okay, replace EEC power relay and repeat QUICK TEST .