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.
2012 Infiniti M56 V8-5.6L (VK56VD)FACTORY OEM SERVICE PROCEDURE
Diagnosis Procedure
SHIFT LOCK SYSTEM
WITH ICC : Diagnosis Procedure
1. CHECK POWER SOURCE (PART 1)
1.Turn ignition switch OFF.
2.Disconnect shift lock relay.
3.Check voltage between shift lock relay vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 2.
NO- GO TO 9.
2. CHECK GROUND CIRCUIT (PART 1)
Check continuity between shift lock relay vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 3.
NO- Repair or replace damaged parts.
3. CHECK SHIFT LOCK RELAY
Check shift lock relay. Component Inspection (Shift Lock Relay).
Is the inspection result normal?
YES- GO TO 4.
NO- Repair or replace damaged parts.
4. CHECK POWER SOURCE (PART 2)
1.Turn ignition switch ON.
2.Check voltage between shift lock relay vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 5.
NO- GO TO 19.
5. CHECK HARNESS BETWEEN SHIFT LOCK RELAY AND A/T SHIFT SELECTOR (PART 1)
1.Turn ignition switch OFF.
2.Disconnect A/T shift selector connector.
3.Check continuity between shift lock relay vehicle side harness connector terminal and A/T shift selector vehicle side harness connector terminal
Is the inspection result normal?
YES- GO TO 6.
NO- Repair or replace damaged parts.
6. CHECK HARNESS BETWEEN SHIFT LOCK RELAY AND A/T SHIFT SELECTOR (PART 2)
Check continuity between shift lock relay vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 7.
NO- Repair or replace damaged parts.
7. CHECK GROUND CIRCUIT (PART 2)
Check continuity between A/T shift selector vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 8.
NO- GO TO 22.
8. CHECK SHIFT LOCK UNIT
Check shift lock unit. Component Inspection (Shift Lock Unit)
Is the inspection result normal?
YES- Check intermittent incident. Intermittent Incident.
NO- Repair or replace damaged parts.
9. CHECK POWER SOURCE (PART 3)
1.Disconnect stop lamp switch connector.
2.Check voltage between stop lamp switch vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 14.
NO- GO TO 10.
10. CHECK HARNESS BETWEEN FUSE BLOCK (J/B) AND STOP LAMP SWITCH (PART 1)
1.Disconnect fuse block (J/B) connector.
2.Check continuity between fuse block (J/B) vehicle side harness connector terminal and stop lamp switch vehicle side harness connector terminal.
Is the inspection result normal?
YES- GO TO 11.
NO- Repair or replace damaged parts.
11. CHECK HARNESS BETWEEN FUSE BLOCK (J/B) AND STOP LAMP SWITCH (PART 2)
Check continuity between fuse block (J/B) vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 12.
NO- Repair or replace damaged parts.
12. DETECT MALFUNCTIONING ITEM (PART 1)
Check the following.
- Harness for short or open between battery and fuse block (J/B). Battery Power Supply.
- Battery
- 10A fuse [No.7, located in the fuse block (J/B)]. Fuse Block - Junction Box (J/B).
- Fuse block (J/B)
Is the inspection result normal?
YES- GO TO 13.
NO- Repair or replace damaged parts.
13. CHECK DTC OF ICC
With CONSULT
Perform "Self Diagnostic Results" in "ICC".
Is any malfunction detected?
YES- Check the DTC detected item. Testing and Inspection.
NO- Check intermittent incident. Intermittent Incident.
14. CHECK STOP LAMP SWITCH (PART 1)
Check stop lamp switch. Component Inspection (Stop Lamp Switch).
Is the inspection result normal?
YES- GO TO 17.
NO- GO TO 15.
15. CHECK INSTALLATION POSITION OF STOP LAMP SWITCH
Adjust stop lamp switch position. Adjustments.
- GO TO 16.
16. CHECK STOP LAMP SWITCH (PART 2)
Check stop lamp switch. Component Inspection (Stop Lamp Switch).
Is the inspection result normal?
YES- INSPECTION END
NO- Repair or replace damaged parts.
17. CHECK HARNESS BETWEEN STOP LAMP SWITCH AND SHIFT LOCK RELAY (PART 1)
Check continuity between stop lamp switch vehicle side harness connector terminal and shift lock relay vehicle side harness connector terminal.
Is the inspection result normal?
YES- GO TO 18.
NO- Repair or replace damaged parts.
18. CHECK HARNESS BETWEEN STOP LAMP SWITCH AND SHIFT LOCK RELAY (PART 2)
Check continuity between stop lamp switch vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 13.
NO- Repair or replace damaged parts.
19. CHECK HARNESS BETWEEN FUSE BLOCK (J/B) AND SHIFT LOCK RELAY (PART 1)
1.Turn ignition switch OFF.
2.Disconnect fuse block (J/B) connector.
3.Check continuity between fuse block (J/B) vehicle side harness connector terminal and shift lock relay vehicle side harness connector terminal.
Is the inspection result normal?
YES- GO TO 20.
NO- Repair or replace damaged parts.
20. CHECK HARNESS BETWEEN FUSE BLOCK (J/B) AND SHIFT LOCK RELAY (PART 2)
Check continuity between fuse block (J/B) vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 21.
NO- Repair or replace damaged parts.
21. DETECT MALFUNCTIONING ITEM (PART 2)
Check the following.
- Harness for short or open between ignition switch and fuse block (J/B). Ignition Power Supply.
- Ignition switch
- 10A fuse [No.3, located in the fuse block (J/B)]. Fuse Block - Junction Box (J/B).
- Fuse block (J/B)
Is the inspection result normal?
YES- Check intermittent incident. Intermittent Incident.
NO- Repair or replace damaged parts.
22. CHECK GROUND CIRCUIT (PART 3)
1.Disconnect PCB harness connector.
2.Check continuity between PCB harness vehicle side harness connector terminal and ground.
Is the inspection result normal?
YES- GO TO 23.
NO- Repair or replace damaged parts.
23. CHECK HARNESS BETWEEN A/T SHIFT SELECTOR AND PCB HARNESS
Check continuity between A/T shift selector vehicle side harness connector terminal and PCB harness vehicle side harness connector terminal.
Is the inspection result normal?
YES- GO TO 24.
NO- Repair or replace damaged parts.
24. CHECK PCB HARNESS
Check continuity between PCB harness connector terminals.
Is the inspection result normal?
YES- Check intermittent incident. Intermittent Incident.
NO- Repair or replace damaged parts.
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
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