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.
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HOMESERVICE MANUALSSUBARU1997IMPREZA L, 2D COUPE, STANDARDREPAIR AND DIAGNOSISENGINE PERFORMANCESYSTEMENGINE CONTROLS - BASIC TESTINGIGNITION CONTROL SYSTEM TESTS
1997 Subaru Impreza L, 2D Coupe, Standard
Ignition Control System Tests
1997 Subaru Impreza L, 2D Coupe, StandardSECTION Ignition Control System Tests
NOTE:
Ensure battery is fully charged before performing tests.
- Check Ignition System For Proper Spark - Remove injector sub-harness and spark plug wire cap from each spark plug. Install a known-good spark plug to plug wire and position spark plug so it is grounded to engine. Crank engine. If a spark does not occur at each spark plug, connect injector sub-harness and spark plug wires and go to next step. If a spark does occur at each spark plug, see FUEL PUMP CIRCUIT TESTS .
- Check Ignition Coil Power Supply Circuit - Turn ignition off and disconnect 3-pin ignition coil harness connector. Turn ignition on. Ensure there is at least 10 volts between ignition coil harness connector terminal No. 2 and ground. If voltage is as specified, go to next step. If voltage is not as specified, repair harness or connectors as necessary.
- Check Ignition Coil - Ensure coil resistance is as specified. See IGNITION COIL RESISTANCE table. If coil resistance is as specified, go to next step. If coil resistance is not as specified, replace ignition coil.
- Check Harness Connector Between Ignition Coil & Ignitor - Turn ignition off. Disconnect 6-pin ignitor connector. Check resistance between ignition coil harness connector terminal No. 1 and ignitor harness terminal No. 5. Check resistance between ignition coil harness connector terminal No. 3 and ignitor harness connector terminal No. 6. See appropriate wiring diagram in WIRING DIAGRAMS article. If resistance is less than one ohm, go to next step. If resistance is greater than one ohm, repair or replace harness connector as necessary.
- Check Input Signal For Ignitor - Turn ignition off. Connect ignition coil and ignitor connectors. Check voltage between ignitor 6-pin harness connector terminal No. 1 and ground, and between terminal No. 2 and ground. See appropriate wiring diagram in WIRING DIAGRAMS article. Crank engine and verify voltage fluctuates between .1 and 3.4 volts. If voltage fluctuates, go to next step. If voltage does not fluctuate, replace ignitor.
- Check Ignitor Harness Connector Ground Circuit - Turn ignition off. Ensure resistance is less than 5 ohms between ignitor harness connector terminal No. 3 and ground. See appropriate wiring diagram in WIRING DIAGRAMS article. If resistance is as specified, go to next step. If resistance is not as specified, repair harness or connectors as necessary.
- Check Harness Connector Between ECM & Ignitor - Turn ignition off. Disconnect ECM connectors. Ensure there is one ohm maximum resistance in circuits between ECM connectors and ignitor harness connector. Check between ECM harness connector, terminal No. 41 and ignitor harness connector terminal No. 1, and between ECM terminal No. 40 and ignitor harness connector terminal No. 2. See appropriate wiring diagram in WIRING DIAGRAMS article.
- On ECM connector, check for continuity between harness connector terminal No. 69 and ignitor 6-pin harness connector terminal No. 3. Ensure there is one megohm resistance between ECM harness connector terminal No. 13 and ground, and terminal No. 14 and ground. If harness resistance is not as specified, repair harness or connectors as necessary. If harness resistance is as specified, inspect and repair ECM connectors. If ECM connectors are okay, replace ECM.
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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.