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B2104






B2104-IGNITION RUN/START CONTROL CIRCUIT LOW





For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.

Theory of Operation

The family of B2100 DTCs typically describes ignition performance related faults. These are often caused by a contradiction of switch status information. For example, if an ECU receives a bussed message indicating ignition switch position but the state of a hardwired ignition circuit indicates another switch position a B2100 series DTC would likely result.

These DTCs can be caused by a number of conditions including:

- loose connections
- missing or blown fuses
- faulty component
- vehicle no start or long crank time

Verify the proper operation of the starting system and verify that this DTC is active before proceeding with the diagnostic test.

- When Monitored:
With the ignition on.

- Set Condition:
The TIPM will set this DTC within 500ms if the Ignition Run/Start circuit voltage is less than the expected value.





1. CHECK FOR ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
1. Turn the ignition on.
2. Using the scan tool, read the DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- If the DTC is stored, check for an intermittent condition. Using the wiring diagram/schematic as a guide, visually inspect the related wiring harness connectors. Look for broken, bent, pushed out or corroded terminals.
- Perform the BODY VERIFICATION TEST Body Verification Test.

2. CHECK (F201) CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Remove fuse number 21.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Did the DTC changed from active to stored?

Yes

- Go To 9

No

- Go To 3

3. CHECK (F202) CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Remove fuse number 28.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Did the DTC changed from active to stored?

Yes

- Go To 12

No

- Go To 4

4. CHECK (F21) CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Remove fuse number 29.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Did the DTC changed from active to stored?

Yes

- Go To 14

No

- Go To 5

5. CHECK (F960) CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Remove fuse number 30.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Did the DTC changed from active to stored?

Yes

- Go To 18

No

- Go To 6

6. (F12) FUSED IGNITION SWITCH OUTPUT (RUN-START) SHORTED TO GROUND




1. Turn the ignition off.
2. Disconnect the TIPM C3 and C10 harness connectors
3. Measure the resistance between ground and the (F12) Fused Ignition Switch Output (Run-Start) circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (F12) Fused Ignition Switch Output (Run-Start) circuit for a short to ground.
- Perform the BODY VERIFICATION TEST Body Verification Test.

No

- Go To 7

7. BLOWER MOTOR
1. Turn the ignition off.
2. Disconnect the Blower Motor.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 8

No

- Replace the Blower Motor.
- Perform the ORC VERIFICATION TEST Occupant Restraint Controller (ORC) Verification Test.

8. (F942) FUSED IGNITION SWITCH OUTPUT (RUN-START) SHORTED TO GROUND




1. Turn the ignition off.
2. Disconnect the TIPM C3 harness connector.
3. Measure the resistance between ground and the (F942) Fused Ignition Switch Output (Run-Start) circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (F12) Fused Ignition Switch Output (Run-Start) circuit for a short to ground.
- Perform the BODY VERIFICATION TEST Body Verification Test.

No

- Replace the TIPM.
- Perform the BODY VERIFICATION TEST Body Verification Test.

9. OCCUPANT RESTRAINT CONTROLLER

WARNING: To avoid possible serious or fatal injury, turn the ignition off, disconnect the battery and wait two minutes before proceeding.

1. Disconnect the ORC C2 harness connector
2. Turn the ignition on.
3. Reconnect the battery.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 10

No

- Replace the ORC.
- Perform the ORC VERIFICATION TEST Occupant Restraint Controller (ORC) Verification Test.

10. PASSENGER AIRBAG ON/OFF SWITCH
1. Turn the ignition off.
2. Disconnect the Passenger Airbag ON/OFF Switch
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 11

No

- Replace the Passenger Airbag Switch.
- Perform the BODY VERIFICATION TEST Body Verification Test.

11. (F201) FUSED IGNITION SWITCH OUTPUT (RUN-START) SHORTED TO GROUND




1. Turn the ignition off.
2. Disconnect the TIPM C8 harness connector.
3. Measure the resistance between ground and the (F201) Fused Ignition Switch Output (Run-Start) circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (F201) Fused Ignition Switch Output (Run-Start) circuit for a short to ground.
- Perform the BODY VERIFICATION TEST Body Verification Test.

No

- Replace the TIPM.
- Perform the BODY VERIFICATION TEST Body Verification Test.

12. POWERTRAIN CONTROL MODULE (GAS) OR ENGINE CONTROL MODULE (DIESEL)
1. Turn the ignition off.
2. Disconnect the PCM C1 or ECM C2 harness connector.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 13

No

- Repair the PCM or ECM.
- Perform the POWERTRAIN VERIFICATION TEST (GAS) Powertrain Verification Test or the POWERTRAIN VERIFICATION TEST (DIESEL) Powertrain Verification Test.

13. (F202) FUSED IGNITION SWITCH OUTPUT (RUN-START) SHORTED TO GROUND




1. Turn the ignition off.
2. Disconnect the TIPM C3 harness connector.
3. Measure the resistance between ground and the (F202) Fused Ignition Switch Output (Run-Start) circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (F202) Fused Ignition Switch Output (Run-Start) circuit for a short to ground.
- Perform the BODY VERIFICATION TEST Body Verification Test.

No

- Replace the TIPM.
- Perform the BODY VERIFICATION TEST Body Verification Test.

14. INSIDE REARVIEW MIRROR
1. Turn the ignition off.
2. Disconnect the Inside Rearview Mirror harness connector.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 15

No

- Repair the Inside Rearview Mirror.
- Perform the BODY VERIFICATION TEST Body Verification Test.

15. TRANSFER CASE SELECTOR SWITCH
1. Turn the ignition off.
2. Disconnect the Transfer Case Selector Switch harness connector.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 16

No

- Repair the Transfer Case Selector Switch.
- Perform the BODY VERIFICATION TEST Body Verification Test.

16. PASSENGER DOOR LOCK SWITCH
1. Turn the ignition off.
2. Disconnect the Passenger Door Lock Switch harness connector.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 17

No

- Repair the Passenger Door Lock Switch.
- Perform the BODY VERIFICATION TEST Body Verification Test.

17. (F21) FUSED IGNITION SWITCH OUTPUT (RUN-START) SHORTED TO GROUND




1. Turn the ignition off.
2. Disconnect the TIPM C3 harness connector.
3. Measure the resistance between ground and the (F21) Fused Ignition Switch Output (Run-Start) circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (F21) Fused Ignition Switch Output (Run-Start) circuit for a short to ground.
- Perform the BODY VERIFICATION TEST Body Verification Test.

No

- Replace the TIPM.
- Perform the BODY VERIFICATION TEST Body Verification Test.

18. O2 SENSOR MODULE (DIESEL)
1. Turn the ignition off.
2. Disconnect the O2 Sensor Module harness connector.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 19

No

- Repair the O2 Sensor Module.
- Perform the BODY VERIFICATION TEST Body Verification Test.

19. ANTILOCK BRAKES MODULE
1. Turn the ignition off.
2. Disconnect the Antilock Brakes Module harness connector.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 20

No

- Repair the Antilock Brakes Module.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

20. FINAL DRIVE CONTROL MODULE
1. Turn the ignition off.
2. Disconnect the Final Drive Control Module harness connector.
3. Turn the ignition on.
4. Using the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 21

No

- Repair the Final Drive Control Module.
- Perform the FDCM VERIFICATION TEST. FDCM Verification Test.

21. (F960) FUSED IGNITION SWITCH OUTPUT (RUN-START) SHORTED TO GROUND




1. Turn the ignition off.
2. Disconnect the TIPM C3 harness connector.
3. Measure the resistance between ground and the (F960) Fused Ignition Switch Output (Run-Start) circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (F960) Fused Ignition Switch Output (Run-Start) circuit for a short to ground.
- Perform the BODY VERIFICATION TEST Body Verification Test.

No

- Replace the TIPM.
- Perform the BODY VERIFICATION TEST Body Verification Test.

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