April 5, 2026: LEMON Manuals is launched! Read the announcement.

Possible Causes

Fuse
Circuit open
Ignition switch
SJB

CAUTION:

Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.

PINPOINT TEST 3 CHART - DTC B1555 - IGNITION RUN CIRCUIT FAILURE OR NO POWER IN RUN

PINPOINT TEST 3		DTC B1555 - IGNITION RUN CIRCUIT FAILURE OR NO POWER IN RUN
STEP	INSPECTION		ACTION
1	CHECK THE VOLTAGE SUPPLY TO THE IGNITION SWITCH Key OFF. Disconnect: Ignition switch C-250. Measure the voltage between ground and: - ignition switch C-250 pin 2, circuit (Y), harness side. - ignition switch C-250 pin 7, circuit (Y), harness side. - ignition switch C-250 pin 9, circuit (Y), harness side. Are the voltages greater than 10 volts?	Yes	Go to next step.
1		No	Verify battery junction box (BJB) fuse 9 (40A) is OK. If OK, repair circuit (Y) for an open. Clear the DTCs. Test the system for normal operation.
2	CHECK THE IGNITION SWITCH Carry out the ignition switch component test. See . Is the ignition switch OK ?	Yes	Go to next step.
2		No	Install a new ignition switch. See IGNITION SWITCH . Clear the DTCs. Test the system for normal operation.
3	CHECK THE VOLTAGE SUPPLY TO THE SMART JUNCTION BOX (SJB) Disconnect: SJB J-2280b. Disconnect: SJB J-2280c. Connect: Ignition switch C-250. Measure the voltage between ground and: - SJB C2280b pin 17, circuit (GY/Y), harness side. - SJB C2280b pin 29, circuit (LG/V), harness side. - SJB C2280c pin 32, circuit (B/LG), harness side. Are the voltages greater than 10 volts?	Yes	Go to next step.
3		No	Repair the affected circuit(s) for an open. Clear the DTCs. Test the system for normal operation.
4	CHECK FOR CORRECT SJB OPERATION Disconnect all the SJB connectors. Check for: corrosion. pushed-out pins. spread terminals. Connect all the SJB connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present?	Yes	Install a new SJB. See SMART JUNCTION BOX (SJB) . Test the system for normal operation.
4		No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. Clear the DTCs. Test the system for normal operation.