Forester, Impreza 2.5L, Legacy, Outback 2.5L & Outback Sport
- Remove and inspect all spark plugs. If spark plugs are okay, reinstall all spark plugs and go to next step. If spark plugs are not okay, replace as necessary.
- Check ignition system for spark. Remove plug wire from each spark plug. DO NOT remove spark plug from cylinder. Install new spark plug or spark plug tester to each plug wire. Make contact of thread portion of spark plug with engine. While opening throttle valve fully, crank engine to check that spark occurs at each cylinder. If spark occurs at each cylinder, check fuel pump system. See FUEL PUMP CIRCUIT TESTS under FUEL SYSTEMS. If spark does not occur at each cylinder, go to next step.
- Remove spark plug cables and check resistance of each cable. See HIGH TENSION WIRE RESISTANCE
table. Replace spark plug cables if resistance is not within specification. If spark plug cables are okay, go to next step.HIGH TENSION WIRE RESISTANCE
Application Ohms No. 1 Spark Plug Cable 5600-10,600 No. 2 & 4 Spark Plug Cables 7300-13,700 No. 3 Spark Plug Cable 5900-11,100 - Turn ignition off. Disconnect 4-pin electrical harness connector from ignition coil and ignitor assembly. Turn ignition on. Using a DVOM, measure power supply voltage of Yellow/Light Green wire (Blue/Green wire on Forester; Yellow/White wire on Impreza 2.5L and Outback Sport) between harness side of ignition coil and ignitor assembly 4-pin electrical harness connector terminal No. 2 and good engine ground point. If voltage is greater than 10 volts, go to next step. If voltage is not greater than 10 volts, repair open circuit in harness between ignition coil and ignitor assembly and ignition switch. Note that wire changes color to Green/Red on all models at Brown 16-pin connector located at top front of engine. Also check for poor contact in all connectors between ignition coil and ignitor assembly and ignition switch. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
- Turn ignition off and leave 4-pin ignition coil and ignitor assembly electrical harness connector disconnected. Using a DVOM, measure ground circuit resistance of Black wire (Green/Black wire on Forester: Green/White wire on Impreza 2.5L and Outback Sport) between harness side of ignition coil and ignitor assembly 4-pin electrical harness connector terminal No. 3 and good engine ground point. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, repair open circuit in harness between ignition coil and ignitor assembly and engine ground point located at right rear of engine. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
- Turn ignition off. Remove ignition coil and ignitor assembly. Using a DVOM, check primary resistance between ignition coil and ignitor assembly terminals No. 1 and 2 for one coil and terminals No 2. and 4 for remaining coil. See Fig 1 . See IGNITION COIL RESISTANCE - OHMS @ 68°F (20°C) table. If primary resistance is as specified, go to next step. If primary resistance is not as specified, replace ignition coil and ignitor assembly.
- Check secondary resistance. To test secondary resistance, connect DVOM between ignition coil and ignitor assembly secondary towers No. 1 and 2, and towers No. 3 and 4. See Fig 2
. See IGNITION COIL RESISTANCE - OHMS @ 68°F (20°C)
table. If secondary resistance is as specified, go to next step. If secondary resistance is not as specified, replace ignition coil and ignitor assembly.IGNITION COIL RESISTANCE - OHMS @ 68°F (20°C)
Application (1) Primary (2) Secondary Forester, Impreza 2.5L, Legacy, Outback 2.5L & Outback Sport 0.66-0.80 10,880-14,720 (1) Measured between ignition coil and ignitor assembly 4-pin terminals No. 1 and 2, and between terminals No. 2 and 4. See Fig 1 . (2) Measured between ignition coil and ignitor assembly secondary towers for cylinders No. 1 and 2 and cylinders No. 3 and 4. See Fig 2 . Insulation resistance between primary terminal and case should be 100 megohms or more. - Turn ignition off. Reconnect 4-pin ignition coil and ignitor assembly electrical harness connector. While cranking engine, monitor voltage on Yellow/Green wire (Blue on Forester; Red/Green wire on Impreza 2.5L and Outback Sport) by backprobing between 4-pin ignition coil and ignitor assembly electrical harness connector terminal No. 1 and good engine ground point. Also monitor voltage on Light Blue wire (Red/Green wire Forester; Blue wire on Impreza 2.5L and Outback Sport) by backprobing between 4-pin ignition coil and ignitor assembly electrical harness connector terminal No. 4 and good engine ground point. Voltage should vary synchronously with engine speed. If voltage is greater than 10 volts at both test points, go to next step. If voltage is not greater than 10 volts at either test point, replace ignition coil and ignitor assembly.
- Turn ignition off. Locate ECM under right side of instrument panel behind glove compartment and disconnect 35-pin electrical harness connector B134. Disconnect ignition coil and ignitor assembly 4-pin electrical harness connector. Using a DVOM, measure resistance of wire between specified terminal on harness side of ECM electrical harness connector and backprobe specified terminal on harness side of ignition coil and ignitor assembly 4-pin electrical harness connector. See ECM-TO-IGNITION COIL & IGNITOR ASSEMBLY TEST POINTS (FORESTER, IMPREZA 2.5L, LEGACY, OUTBACK 2.5L & OUTBACK SPORT) table. If resistance is less than one ohm, go to next step. If resistance is not less than one ohm, repair open circuit in harness between ECM and ignition coil and ignitor assembly. Also check for poor contact in all connectors between ECM and ignition coil and ignitor assembly. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
- Leave ECM and ignition coil and ignitor assembly electrical harness connectors disconnected. Using a DVOM, measure resistance between specified terminal on harness side of ECM electrical harness connector and good chassis ground point. See ECM-TO-IGNITION COIL & IGNITOR ASSEMBLY TEST POINTS (FORESTER, IMPREZA 2.5L, LEGACY, OUTBACK 2.5L & OUTBACK SPORT) table. If resistance is greater than one megohm, go to next step. If resistance is not greater than one megohm, repair short circuit in harness between ECM and ignition coil and ignitor assembly. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
- Check for poor contact of terminals in connectors between ECM and ignition coil and ignitor assembly. If poor contact exists in any connector, repair as required. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If poor contact does not exist, check fuel pump circuit. See FUEL PUMP CIRCUIT TESTS
under FUEL SYSTEMS.ECM-TO-IGNITION COIL & IGNITOR ASSEMBLY TEST POINTS (FORESTER, IMPREZA 2.5L, LEGACY, OUTBACK 2.5L & OUTBACK SPORT)
Application, ECM Harness Connector & Terminal No. ECM Harness Connector Wire Color (1) Ignition Coil & Ignitor Assembly Terminal No. Ignition Coil & Ignitor Assembly Terminal Wire Color Legacy & Outback 2.5L 35-Pin B134 25 Red/Yellow 1 Yellow/Green 26 Red/Black 4 Light Blue Forester 35-Pin B134 25 Green/White 1 Blue 26 Brown/Yellow 4 Red/Green Impreza 2.5L & Outback Sport 35-Pin B134 25 Yellow/Blue 1 Red/Green 26 Green/White 4 Blue (1) Wire changes color at Brown 16-pin connector located at top front of engine.