Diagnostic Routine C
Diagnostic Routine C
Diagnostic Overview
No Power in ON - Vehicles with an Ignition Switch
Refer to Wiring Diagram Set 13 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
When the ignition switch is turned to the ON position, a voltage signal is sent to the BCM (Body Control Module). The BCM (Body Control Module) then activates the ignition relay and accessory relay, which distribute fused voltage to various components. The BCM (Body Control Module) uses a FET (Field-Effect Transistor) to control the relays. The ignition relay receives voltage from BJB (Battery Junction Box) fuse 23 (5A).
DTC Fault Trigger Conditions
Special Tool(s)
Pinpoint Test
1. CHECK FOR IGNITION ON MODE
1. NOTE: The air bag warning indicator in the IPC (Instrument Panel Cluster) only illuminates and proves out when the vehicle successfully enters ON mode.
Monitor the air bag warning indicator while attempting to enter ON mode.
Did the air bag warning indicator illuminate for approximately 6 seconds and then go out?
2. CHECK FOR IGNITION ON VOLTAGE AT THE BCM (Body Control Module)
1. Ignition OFF.
2. Disconnect: BCM (Body Control Module) C2280C.
3. Ignition ON.
4. Measure:
Is the voltage greater than 11 volts?
3. CHECK THE IGNITION ON CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Disconnect: Ignition Switch.
3. Measure:
Is the resistance less than 3 ohms?
4. CHECK BCM (Body Control Module) DTCs (Diagnostic Trouble Codes)
1. Using the scan tool, perform the BCM (Body Control Module) self-test.
Is BCM (Body Control Module) DTC (Diagnostic Trouble Code) B10E7:12, B10E7:14 or B112A:12 present?
5. CHECK THE IGNITION RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
1. Ignition OFF.
2. Disconnect: Ignition Relay.
3. Disconnect: BCM (Body Control Module) C2280D.
4. Ignition ON.
5. Measure:
Is any voltage present?
6. CHECK THE IGNITION RELAY COIL VOLTAGE CIRCUIT
1. Ignition OFF.
2. Disconnect: Ignition Relay.
3. Ignition ON.
4. Measure:
Is the voltage greater than 11 volts?
7. CHECK THE IGNITION RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Disconnect: BCM (Body Control Module) C2280D.
3. Measure:
Is the resistance greater than 10,000 ohms?
8. CHECK THE IGNITION RELAY CONTROL CIRCUIT FOR AN OPEN
1. Measure:
Is the resistance less than 3 ohms?
9. CHECK THE ACCESSORY RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
1. Ignition OFF.
2. Disconnect: Accessory Relay.
3. Disconnect: BCM (Body Control Module) C2280B.
4. Ignition ON.
5. Measure:
Is any voltage present?
10. CHECK THE IGNITION RELAY CONTACT VOLTAGE CIRCUIT
1. Ignition OFF.
2. Disconnect: Ignition Relay.
3. Ignition ON.
4. Measure:
Is the voltage greater than 11 volts?
11. CHECK VEHICLE OPTIONS
1. Check the vehicle for heated seats, roof opening panel, parking aid system and a rear view camera system.
Is the vehicle equipped with heated seats, roof opening panel, parking aid system and/or rear view camera system?
12. CHECK THE IGNITION RELAY VOLTAGE OUTPUT CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Measure:
Is the resistance less than 3 ohms?
13. CHECK THE ACCESSORY RELAY COIL VOLTAGE CIRCUIT
1. Ignition OFF.
2. Disconnect: Accessory Relay.
3. Ignition ON.
4. Measure:
Are the voltages greater than 11 volts?
14. CHECK THE ACCESSORY RELAY
NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning of this system. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
1. Measure:
Did the light illuminate?
15. CHECK THE ACCESSORY RELAY CONTROL CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Disconnect: BCM (Body Control Module) C2280B.
3. Measure:
Is the resistance less than 3 ohms?
16. CHECK FOR CORRECT BCM (Body Control Module) OPERATION
1. Disconnect and inspect all BCM (Body Control Module) connectors.
2. Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
3. Reconnect the BCM (Body Control Module) connectors and all previously disconnected exterior system connectors. Make sure they seat and latch correctly.
4. Operate the system and determine if the concern is still present.
Is the concern still present?
