Pinpoint Test C: DTC B1520

Anti-Theft

Pinpoint Test C: DTC B1520

Refer to Wiring Diagram Set 117, Remote Keyless Entry and Alarm for schematic and connector information [1][2]Diagrams By Number.

Normal Operation

When the alarm system is armed, the Smart Junction Box (SJB) monitors the hood ajar switch. If the hood is opened while the alarm is armed, the hood ajar switch removes ground from the signal circuit. This signals the SJB (Smart Junction Box) that an unauthorized intrusion to the engine compartment has occurred and the SJB (Smart Junction Box) activates the perimeter alarm.

- DTC B1520 (Hood Switch Circuit Open)- an on-demand DTC that sets when the SJB (Smart Junction Box) detects an open in the hood switch circuit during the self-test. This DTC sets if the hood is open during a self-test.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Hood switch

- SJB (Smart Junction Box)

PINPOINT TEST C : DTC B1520

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

C1 CHECK THE HOOD SWITCH

- Disconnect: Hood Switch C127.

- Connect a fused jumper wire between the hood switch C127-1, circuit CPL25 (BU/OG), harness side and the hood switch C127-2, circuit GD123 (BK/GY), harness side.





- Clear the SJB (Smart Junction Box) DTCs.

- Repeat the SJB (Smart Junction Box) self-test.

Is the SJB (Smart Junction Box) DTC B1520 retrieved?

Yes
REMOVE the jumper wire. GO to C2.

No
REMOVE the jumper wire. INSTALL a new hood switch. TEST the system for normal operation.

C2 CHECK THE HOOD SWITCH GROUND CIRCUIT FOR AN OPEN

- Measure the resistance between the hood switch C127-2, circuit GD123 (BK/GY), harness side and ground.





Is the resistance less than 5 ohms?

Yes
GO to C3.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

C3 CHECK THE HOOD SWITCH SENSE CIRCUIT FOR AN OPEN

- Disconnect: SJB (Smart Junction Box) C2280F.

- Measure the resistance between the SJB (Smart Junction Box) C2280F-10, circuit CPL25 (BU/OG), harness side and the hood switch C127-1, circuit CPL25 (BU/OG), harness side.





Is the resistance less than 5 ohms?

Yes
GO to C4.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

C4 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION

- Disconnect all the SJB (Smart Junction Box) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the SJB (Smart Junction Box) 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 (Smart Junction Box). REPEAT the self-test. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.