DTC B2785: Ignition Switch On Malfunction & DTC B2786: Ignition Switch Off Malfunction
NOTE:
DTC B2785 may be caused by a short circuit in ignition switch circuit or ignition switch remains in ON position. DTC B2786 may be caused by a open circuit in ignition switch circuit or ignition switch remains in OFF position. EFI relay may also be referred to as EFI main relay.
- Check Voltage Between ECM Terminals
Remove glove box for access to Engine Control Module (ECM). Turn ignition on. Using voltmeter, check voltage between ECM terminals +B (Light Green wire) and E1 (Brown wire). See Fig 1. Voltage should be 9-14 volts. - If voltage is not within specification, go to next step. If voltage is within specification, go to TROUBLE SHOOTING SYMPTOMS table under TROUBLE SHOOTING for system diagnosis by trouble symptom.
- Check For Open E1 Circuit
Check for open circuit between ECM terminal E1 (Brown wire) and body ground. If no open circuit exists, go to next step. If open circuit exists, repair wiring or connectors as necessary. - Check EFI Relay
Remove EFI relay from the fuse/relay box at driver's side front corner of engine compartment near the battery. Check EFI relay operation. See EFI RELAY under COMPONENT TESTS. If EFI relay is okay, go to next step. If EFI relay is defective, replace EFI relay. - Check EFI Fuse
Remove EFI fuse from the fuse/relay box at driver's side front corner of engine compartment near the battery. Using ohmmeter, ensure continuity exists across the fuse. If fuse is okay, go to next step. If fuse is blown, check for short circuit in wiring circuit to EFI fuse. See WIRING DIAGRAMS . Replace EFI fuse and repair wiring circuit as necessary. - Check For Open EFI Relay Circuit
Using ohmmeter, check for open circuit between EFI relay and the battery, and between EFI relay and ECM. See WIRING DIAGRAMS . EFI relay is located in fuse/relay box at driver's side front corner of engine compartment near the battery. If no open circuit exists, go to next step. If open circuit exists, repair wiring or connectors as necessary. - Check IGN Fuse
Remove IGN fuse from fuse/relay box at lower corner of driver's side of instrument panel, near steering column. Using ohmmeter, ensure continuity exists across the fuse. If fuse is okay, go to next step. If fuse is blown, check for short circuit in wiring circuit to IGN fuse. See WIRING DIAGRAMS . Replace IGN fuse and repair wiring circuit as necessary. - Check Ignition Switch
Check ignition switch operation. See IGNITION SWITCH under COMPONENT TESTS. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch. - Check For Open Ignition Switch Circuit & EFI Relay Ground Circuit
Using ohmmeter, check for open circuit between ignition switch and EFI relay, and for open circuit between EFI relay and body ground. See WIRING DIAGRAMS . If no open circuit exists, go to next step. If open circuit exists, repair wiring or connectors as necessary. - Replace ECM. See ENGINE CONTROL MODULE (ECM) under REMOVAL & INSTALLATION. Ensure ignition keys are registered to the ECM. See IGNITION KEY REGISTRATION under PROGRAMMING.