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Pinpoint Test E: DTC B2A20




Steering Column Switches

Pinpoint Tests

Pinpoint Test E: B2A20

Refer to Wiring Diagram Set 13, Power Distribution/SJB for schematic and connector information. Diagrams By Number

Normal Operation

The ignition switch is spring-loaded to automatically return to the RUN position after being placed in the START position. A microprocessor in the Smart Junction Box (SJB) monitors the voltage output from the ignition switch while the switch is in the START position. This microprocessor is also connected to several different circuits and a short to voltage on any one of them could cause DTC B2A20 to set.

- DTC B2A20 (Ignition Stuck in START) - The SJB continuously monitors the ignition switch state, if the SJB receives a START signal for more than 30 seconds, DTC B2A20 will be set.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Starter relay
- Ignition switch
- SJB
- PCM
- Audio Control Module (ACM)


PINPOINT TEST E: B2A20

NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.

NOTE: Verify that battery voltage is 10 volts or greater.

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E1 CHECK THE IGNITION SWITCH MECHANICAL FUNCTION


- Inspect the ignition switch for mechanical function. Refer to the Ignition Switch - Mechanical Component Test. Component Tests and General Diagnostics
- Is the ignition switch OK?

Yes
GO to E2.

No
INSTALL a new ignition switch. REFER to Ignition Switch Ignition Switch. TEST the system for normal operation.

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E2 CHECK THE IGNITION SWITCH FOR A SHORT


- Carry out the Ignition Switch - Electrical Component Test. Component Tests and General Diagnostics
- Is the ignition switch OK?

Yes
For vehicles equipped with a diesel engine, GO to E3.

For vehicles equipped with a gasoline engine, GO to E7.

No
INSTALL a new ignition switch. REFER to Ignition Switch Ignition Switch. CLEAR the DTCs. REPEAT the self-test.

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E3 ISOLATE THE ACM POWER CIRCUIT


- Ignition OFF.
- Disconnect: Ignition Switch C250.
- Disconnect: SJB Fuse 28 (5A).
- Measure the voltage between ignition switch C250-5, circuit CDC35 (BU/WH), harness side and ground.




- Is any voltage present?

Yes
GO to E5.

No
GO to E4.

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E4 ISOLATE THE ACM


- Disconnect: ACM C240A.
- Measure the voltage between ACM C240A-15, circuit CBP28 (GY/VT), harness side and ground.




- Is any voltage present?

Yes
REPAIR circuit CBP28 (GY/VT). CLEAR the DTC. REPEAT the self-test.

No
INSTALL a new ACM. REFER to Information and Entertainment Systems Audio Control Module (ACM). CLEAR the DTC. REPEAT the self-test.

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E5 ISOLATE THE STARTER RELAY INPUT CIRCUIT


- Disconnect: SJB C2280E.
- Measure the voltage between ignition switch C250-5, circuit CDC35 (BU/WH), harness side and ground.




- Is any voltage present?

Yes
GO to E6.

No
REPAIR circuit CDC35 (BU/WH). CLEAR the DTC. REPEAT the self-test.

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E6 ISOLATE THE SJB


- Disconnect: SJB C2280B.
- Measure the voltage between ignition switch C250-5, circuit CDC35 (BU/WH), harness side and ground.




- Is any voltage present?

Yes
REPAIR circuit CDC35 (BU/WH). CLEAR the DTCs. REPEAT the self-test.

No
GO to E15.

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E7 CHECK THE PCM START SIGNAL INPUT CIRCUIT FOR A SHORT TO VOLTAGE


- Disconnect: Starter Diode.
- Measure the voltage between ignition switch C250-5, circuit CDC35 (BU/WH), harness side and ground.




- Is any voltage present?

Yes
GO to E8.

No
GO to E9.

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E8 ISOLATE THE PCM START SIGNAL INPUT CIRCUIT


- Disconnect: PCM C1551B (6.8L engine).
- Disconnect: PCM C175B (All other gas engines).
- Measure the voltage between ignition switch C250-5, circuit CDC35 (BU/WH), harness side and ground.




- Is any voltage present?

Yes
REPAIR circuit CDC35 (BU/WH). CLEAR the DTCs. REPEAT the self-test.

No
INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. CLEAR the DTCs. REPEAT the self-test.

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E9 CHECK THE STARTER DIODE


- Carry out a diode test on the starter diode.
- Does the diode pass the test?

Yes
GO to E10.

No
INSTALL a new diode. CLEAR the DTCs. REPEAT the self-test.

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E10 CHECK THE SJB START SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE


- Disconnect: SJB C2280B.
- Measure the voltage between SJB C2280B-32, circuit CE336 (GN/WH), harness side and ground.




- Is any voltage present?

Yes
GO to E13.

No
GO to E11.

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E11 CHECK THE ACM START POWER CIRCUIT FOR A SHORT TO VOLTAGE


- Measure the voltage between SJB C2280B-2, circuit CBP28 (GY/VT), harness side and ground.




- Is any voltage present?

Yes
GO to E12.

No
GO to E15.

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E12 CHECK THE ACM FOR A SHORT TO VOLTAGE


- Disconnect: ACM C240A.
- Measure the voltage between SJB C2280B-2, circuit CBP28 (GY/VT), harness side and ground.




- Is any voltage present?

Yes
REPAIR circuit CBP28 (GY/VT). CLEAR the DTCs. REPEAT the self-test.

No
INSTALL a new ACM. REFER to Information and Entertainment Systems Audio Control Module (ACM). CLEAR the DTC. REPEAT the self-test.

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E13 ISOLATE THE PCM


- Disconnect: PCM C175B.
- Measure the voltage between SJB C2280B-32, circuit CE336 (GN/WH), harness side and ground.




- Is any voltage present?

Yes
GO to E14.

No
INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. CLEAR the DTCs. REPEAT the self-test.

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E14 CHECK THE STARTER RELAY CIRCUIT FOR A SHORT TO VOLTAGE


- Disconnect: Transmission Range (TR) Sensor C167 (Vehicles equipped with a 4R75E transmission).
- Disconnect: Starter Relay (Vehicles equipped with a TorqShift transmission).
- For all vehicles, measure the voltage between SJB C2280B-32, circuit CE336 (GN/WH), harness side and ground.




- For vehicles equipped with a 4R75E transmission, measure the voltage between TR Sensor C167-10, circuit CET40 (GN/OG), harness side and ground.




- Is any voltage present?

Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

No
GO to E15.

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E15 CHECK FOR CORRECT SJB OPERATION


- Check SJB connectors C2280B and C2280E for:

- corrosion.
- pushed-out pins.
- spread terminal.
- Connect: SJB C2280B.
- Connect: SJB C2280E.
- Make sure the connectors are seated correctly, then operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new SJB, REFER to Multifunction Electronic Modules Service and Repair. CLEAR the DTCs. REPEAT the self-test.

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

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