Pinpoint Test C: The Courtesy Lamps Do Not Illuminate With The Liftgate Or The Liftgate Glass Open
Interior Lighting
Pinpoint Test C: The Courtesy Lamps Do Not Illuminate With the Liftgate Or The Liftgate Glass Open
Refer to Wiring Diagram Set 117, Remote Keyless Entry and Alarm for schematic and connector information Electrical Diagrams.
Normal Operation
The SJB (Smart Junction Box) sends a voltage signal to the Liftgate/Trunk Module (LTM) (vehicles with a power liftgate) or to the liftgate glass ajar switch and the liftgate ajar switch (vehicles with a manual liftgate). The voltage signal is routed to ground when the liftgate glass or liftgate are closed. When the liftgate or liftgate glass is opened, the signal to ground is interrupted, indicating an open door or liftgate.
- DTC B2721 (Liftgate/Decklid Ajar Output Short to Ground or Open)- a continuous and on-demand DTC that sets when the LTM (Liftgate/Trunk Module) detects a short to ground from the SJB (Smart Junction Box) liftgate ajar input circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Liftgate ajar switch (integrated into the liftgate latch)
- Liftgate glass ajar switch (integrated into the liftgate latch)
- LTM (Liftgate/Trunk Module)
- SJB (Smart Junction Box)
PINPOINT TEST C : THE COURTESY LAMPS DO NOT ILLUMINATE WITH THE LIFTGATE OR THE LIFTGATE GLASS OPEN
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings.
C1 CHECK THE LIFTGATE TYPE
- Identify the vehicle liftgate type.
Is the vehicle equipped with a power liftgate?
Yes
GO to C2.
No
GO to C7.
C2 CHECK THE LIFTGATE GLASS AJAR PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: LTM (Liftgate/Trunk Module) DataLogger.
- Monitor the LTM (Liftgate/Trunk Module) liftgate glass ajar PID (GLASS_POS) while opening and closing the liftgate glass.
Does the liftgate glass ajar PID value agree with the liftgate glass ajar positions?
Yes
GO to C5.
No
GO to C3.
C3 CHECK THE LIFTGATE GLASS AJAR SWITCH (POWER LIFTGATE)
- Disconnect: Liftgate Glass Ajar Switch C4040.
Do the courtesy lamps illuminate?
Yes
INSTALL a new liftgate glass latch. TEST the system for normal operation.
No
GO to C4.
C4 CHECK THE LIFTGATE GLASS AJAR SWITCH SIGNAL CIRCUIT FOR A SHORT TO GROUND (POWER LIFTGATE)
- Ignition OFF.
- Disconnect: LTM (Liftgate/Trunk Module) C4174B.
- Measure the resistance between the LTM (Liftgate/Trunk Module) C4174B-18, circuit CPR50 (BN/BU), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to C12.
No
REPAIR circuit CPR50 (BN/BU) for a short to ground. TEST the system for normal operation.
C5 CHECK THE LTM (Liftgate/Trunk Module)
- Ignition OFF.
- Disconnect: LTM (Liftgate/Trunk Module) C4174B.
Do the courtesy lamps illuminate?
Yes
GO to C12.
No
GO to C6.
C6 CHECK THE LIFTGATE AJAR SWITCH SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Disconnect: SJB (Smart Junction Box) C2280C.
- Measure the resistance between the SJB (Smart Junction Box) C2280C-16, circuit CPL58 (GY/OG), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to C11.
No
REPAIR circuit CPL58 (GY/OG) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
C7 CHECK THE COURTESY LAMP OPERATION (MANUAL LIFTGATE)
NOTE: Make sure the liftgate glass is closed.
- Open the liftgate.
Do the courtesy lamps illuminate?
Yes
CLOSE the liftgate. GO to C8.
No
GO to C9.
C8 CHECK THE LIFTGATE GLASS AJAR SWITCH (MANUAL LIFTGATE)
- Disconnect: Liftgate Glass Ajar Switch C4040.
Do the courtesy lamps illuminate?
Yes
INSTALL a new liftgate glass latch. TEST the system for normal operation.
No
REPAIR circuit CPR50 (BN/BU) for a short to ground. TEST the system for normal operation.
C9 CHECK THE LIFTGATE AJAR SWITCH (MANUAL LIFTGATE)
- Disconnect: Liftgate Ajar Switch C457.
Do the courtesy lamps illuminate?
Yes
INSTALL a new liftgate latch. TEST the system for normal operation.
No
GO to C10.
C10 CHECK THE LIFTGATE AJAR SWITCH SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Disconnect: SJB (Smart Junction Box) C2280C.
- Measure the resistance between the SJB (Smart Junction Box) C2280C-16, circuit CPL58 (GY/OG), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to C11.
No
REPAIR circuit CPL58 (GY/OG) for a short to ground. TEST the system for normal operation.
C11 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). 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.
C12 CHECK FOR CORRECT LTM (Liftgate/Trunk Module) OPERATION
- Disconnect all the LTM (Liftgate/Trunk Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the LTM (Liftgate/Trunk Module) 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 LTM (Liftgate/Trunk Module). 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. CLEAR the DTCs. REPEAT the self-test.