Code 15: Ignition Output Signal

NOTE: For wiring diagrams, see WIRING DIAGRAMS article. For vacuum diagrams, see VACUUM DIAGRAMS article.

Turn ignition off. Disconnect alternator sense fuse in under-hood relay box for 10 seconds to reset ECU. Start engine and observe CHECK ENGINE and Red LED lights. If lights are off, problem is intermittent. Check for poor or loose connections at ignitor, Red/Blue wire in connectors C439-C257 and C403-C312. Test drive and check again.
If CHECK ENGINE light is on and Red LED indicates Code 15, turn ignition off. Disconnect 4-pin connector on ignitor unit. Turn ignition on. Measure voltage between Black/Yellow (positive) wire terminal and ground.
If battery voltage is present, proceed to step 4). If battery voltage is not present, repair open in Black/Yellow wire between the ignitor unit and ignition switch.
Turn ignition off. Connect ECU test harness between ECU and ECU connector. Reconnect 4-pin ignitor connector. Turn ignition on. Individually, measure voltage between ECU terminals B15 (positive), B16 (negative), and A18 (ground). See Figure . If battery voltage is present in any of these terminals, go to step 5). If battery voltage is not present, go to step 6).
If battery voltage is present, substitute a known good ECU and recheck. If condition goes away, replace original ECU.
If battery voltage does not exist, turn ignition off. Disconnect 4-pin connector from ignitor unit, and ECU connector "B". Check continuity of Red/Blue wire between ECU terminals B15, B16 and ignitor unit.
If no continuity exists, repair open in Red/Blue wire between B15, B16 and ignitor. If continuity exists, check continuity to body ground on Red/Blue wire of ignitor unit 4-pin connector.
If no continuity exists, replace ignitor unit. If continuity exists, repair short in Red/Blue wire and/or replace ignitor unit.