Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1998 Cadillac DeVille BaseFACTORY OEM SERVICE PROCEDURE
Injector Coil Test ECT Not Between 50-95°F
- If powertrain OBD system check has been performed, go to next step. If powertrain OBD system check has not been performed, perform powertrain OBD system check. See POWERTRAIN OBD SYSTEM CHECK in TESTS W/CODES article.
- Connect scan tool to data link connector. Using scan tool, check engine coolant temperature. If 50-95°F (10-35°C) is not displayed, go to next step. If 50-95°F (10-35°C) is displayed, perform INJECTOR COIL TEST - ECT BETWEEN 50-95°F test.NOTE: Perform step 3) on each injector.
- Turn ignition switch to LOCK position. Relieve fuel pressure. Disconnect fuel injector harness connectors. Using fuel injector adapter, connect Fuel Injector Tester (J-39021) to fuel injector. Connect fuel injector tester power leads to appropriate battery terminals. Set amperage supply selector switch on fuel injector tester to Coil Test 0.5-amp position. Connect DVOM to injector tester. Depress PUSH TO START TEST button. Record highest voltage reading other than those greater than 9.5 volts. Subtract any other voltage reading observed from highest voltage reading. If difference is greater than 0.6 volt, go to next step. If difference is not greater than 0.6 volt, perform injector balance test. See FUEL INJECTOR BALANCE TEST.
- Replace any injector(s) that had any of the following results: initial reading greater than 9.5 volts, erratic reading or difference is greater than 0.6 volt. After repairs are complete, perform injector balance test. See FUEL INJECTOR BALANCE TEST.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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