Steering Column Switches

Special Tool(s)

	Flex Probe Kit 105-R025D or equivalent
	Fluke 77-IV Digital Multimeter FLU77-4 or equivalent
	Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool

Principles of Operation

Ignition Switch

NOTE: The Smart Junction Box (SJB) is also identified as the Generic Electronic Module (GEM).

The ignition switch has 4 possible positions:

• OFF
• ACC
• RUN
• START

The ignition switch is controlled by the ignition lock cylinder with a key. When the ignition lock cylinder is turned using the key, a mechanical connection positions the ignition switch to the selected position and allows the ignition switch to send voltage to the SJB and Battery Junction Box (BJB). The ignition switch contains a key-in-ignition switch and a key removal inhibit solenoid.

Key-In-Ignition Switch

The key-in-ignition switch is hardwired to the Instrument Panel Cluster (IPC). The switch allows the IPC to detect when the key has been inserted in the ignition switch. The IPC uses this information for the brake shift interlock system and the chime warning system. For information on the brake shift interlock system, refer to Section 307-05 . For information on the chime warning system, refer to Section 413-01 .

Key Removal Inhibit Solenoid

The key removal inhibit solenoid (also known as the key release interlock actuator) is an electronically controlled solenoid that prevents the ignition lock cylinder from being turned to the OFF position unless the selector lever is in the PARK position. The key removal inhibit solenoid is part of the ignition switch.

Multifunction Switch

The multifunction switches control various components electrically. The headlamp switch sends constant voltage to the headlamps when placed in the ON position, while the flash-to-pass is a momentary switch used to send voltage to the headlamp high beams only. The headlamp high beam/low beam switch sends voltage to the low or high beam headlamps while the headlamps are on. The turn signal switch portion of the multifunction switch operates the left and right turn signals. The windshield wiper switch function uses a ground signal to activate the various wiper modes and the wiper/washer.

For diagnosis and testing of the multifunction switch, refer to Section 417-01 for headlamps and turn signal concerns, and Section 501-16 for wiper and washer concerns.

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of mechanical or electrical damage.

  Visual Inspection Chart

NOTE: For multifunction switch concerns, refer to one of the following sections:

• Exterior Lighting, Section 417-01 .
• Wipers and Washers, Section 501-16 .

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

4. NOTE: Make sure to use the latest scan tool software release.

   If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).

5. NOTE: The Vehicle Communication Module (VCM) LED prove out confirms power and ground from the DLC are provided to the VCM .

   If the scan tool does not communicate with the VCM :
   • check the VCM connection to the vehicle.
   • check the scan tool connection to the VCM .
   • refer to Section 418-00 , No Power To The Scan Tool, to diagnose no power to the scan tool.

6. If the scan tool does not communicate with the vehicle:
   • verify the ignition key is in the ON position.
   • verify the scan tool operation with a known good vehicle.
   • refer to Section 418-00 to diagnose no response from the PCM.

7. Carry out the network test.
   • If the scan tool responds with no communication for one or more modules, refer to Section 418-00 .
   • If the network test passes, retrieve and record Continuous Memory Diagnostic Trouble Codes (CMDTCs).

8. Clear the continuous DTCs and carry out the self-test diagnostics for the SJB .

9. If the DTCs retrieved are related to the concern, go to the Smart Junction Box (SJB) DTC Chart. For all other DTCs, refer to the Diagnostic Trouble Code (DTC) Chart in Section 419-10 .

10. If no DTCs related to the concern are retrieved, GO to Symptom Chart .

 Smart Junction Box (SJB) DTC Chart

Symptom Chart

Pinpoint Tests

Pinpoint Test A: No Power in All Ignition Switch Positions

Refer to Wiring Diagrams Cell 13 , Power Distribution/SJB for schematic and connector information.

Normal Operation

The ignition switch receives fused battery voltage from Smart Junction Box (SJB) fuse 27 (20A) along circuit SPB27 (BU/RD), this voltage is then sent to the SJB and the Battery Junction Box (BJB) for various systems depending on the ignition switch position. The ignition switch has 4 possible positions:

• OFF, voltage is sent to the SJB for the key-in ignition system. Refer to Section 413-01 to diagnose any key-in ignition concerns.
• ACC, voltage is sent to the SJB run/accessory bus along circuit CDC33 (VT/GN).
• RUN, voltage is sent along circuit CE612 (GY/VT) to the:
  • SJB run/start bus
  • SJB internal microprocessor
  • start diode
  • BJB fuse 39 (5A)
  • BJB fuse 45 (5A)
• START, voltage is sent to the SJB start bus along circuit CDC35 (BU/WH).

This pinpoint test is intended to diagnose the following:
• Fuse(s)
• Wiring, terminals or connectors
• Ignition switch
• SJB

PINPOINT TEST A: NO POWER IN ALL IGNITION SWITCH POSITIONS

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

Pinpoint Test B: No Power in ACC

Refer to Wiring Diagrams Cell 13 , Power Distribution/SJB for schematic and connector information.

Normal Operation

When the ignition switch is turned to the ACC position, fused battery voltage is sent to the Smart Junction Box (SJB) run/accessory bus along circuit CDC33 (VT/GN).

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Ignition switch
• SJB

PINPOINT TEST B: NO POWER IN ACC

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

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

Pinpoint Test C: No Power in RUN

Refer to Wiring Diagrams Cell 13 , Power Distribution/SJB for schematic and connector information.

Normal Operation

When the ignition switch is placed in the RUN position, fused ignition voltage is sent to the Smart Junction Box (SJB) and the Battery Junction Box (BJB) along circuit CE612 (GY/VT).

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Ignition switch
• SJB

PINPOINT TEST C: NO POWER IN RUN

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

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

Pinpoint Test D: No Power in START

Refer to Wiring Diagrams Cell 13 , Power Distribution/SJB for schematic and connector information.

Normal Operation

When the ignition switch is placed in the START position, fused ignition voltage is sent to the Smart Junction Box (SJB) start bus along circuit CDC35 (BU/WH).

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Ignition switch
• SJB

PINPOINT TEST D: NO POWER IN START

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

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

Pinpoint Test E: DTC B2A20

Refer to Wiring Diagrams Cell 13 , Power Distribution/SJB for schematic and connector information.

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.

• DTC B2A20 (Ignition Stuck in START) — 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
• Ignition switch
• ACM
• PCM
• SJB
• Starter relay

PINPOINT TEST E: DTC B2A20

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

Pinpoint Test F: DTCs B2844 and U2472

Refer to Wiring Diagrams Cell 13 , Power Distribution/SJB for schematic and connector information.

Normal Operation

Microprocessors in the Smart Junction Box (SJB) continuously monitor the ignition switch state.

If DTC U2472 was set immediately following an SJB on-demand self test. Clear the SJB DTCs and repeat the self-test making sure that the ignition is in RUN. If DTC U2472 returns again, continue with Pinpoint Test F.

• DTC B2844 (Ignition Fault) — If the SJB receives an invalid ignition state (one or more ignition signals at the same time) during normal operation, DTC B2844 will be set.
• DTC U2472 (Unexpected Ignition State) — If the SJB does not receive the ignition RUN signal or cannot detect the ignition switch state during the SJB self-test, DTC U2472 will be set.

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Ignition switch
• SJB

PINPOINT TEST F: DTCs B2844 AND U2472

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

Pinpoint Test G: The Ignition Key Cannot Be Returned to the OFF Position

Refer to Wiring Diagrams Cell 37 , Shift Interlock for schematic and connector information.

Normal Operation

The key removal inhibit solenoid (part of the ignition switch) receives battery voltage from Smart Junction Box (SJB) fuse 27 (20A) through circuit SBP27 (BU/RD). When the selector lever is moved out of the PARK position, the park range switch (part of the selector lever) closes and connects circuit CDC41 (WH/BN) to circuit GD139 (BK/YE), providing ground to the key removal inhibit solenoid. The key removal inhibit solenoid activates and prevents the ignition lock cylinder from being turned to the OFF position and the key removed.

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Ignition switch
• Ignition lock cylinder
• Selector lever
• Steering column lock module

PINPOINT TEST G: THE IGNITION KEY CANNOT BE RETURNED TO THE OFF POSITION

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

Pinpoint Test H: The Ignition Key Can be Turned to the OFF Position When the Selector Lever is not in PARK

Refer to Wiring Diagrams Cell 37 , Shift Interlock for schematic and connector information.

Normal Operation

The key removal inhibit solenoid (part of the ignition switch) receives battery voltage from Smart Junction Box (SJB) fuse 27 (20A) through circuit SBP27 (BU/RD). When the selector lever is moved out of the PARK position, the park range switch (part of the selector lever) closes and connects circuit CDC41 (WH/BN) to circuit GD139 (BK/YE), providing ground to the key removal inhibit solenoid. The key removal inhibit solenoid activates and prevents the ignition lock cylinder from being turned to the OFF position and the key removed.

This pinpoint test is intended to diagnose the following:
• Wiring, terminals or connectors
• Ignition switch
• Selector lever

PINPOINT TEST H: THE IGNITION KEY CAN BE TURNED TO THE OFF POSITION WHEN THE SELECTOR LEVER IS NOT IN PARK

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

Component Tests

Ignition Switch — Mechanical

The following conditions can cause difficulty in operating the ignition switch and lock cylinder:

• Burrs on the lock cylinder key
• Insufficient lube on the lock cylinder
• Binding lock cylinder
• Burrs or foreign material around the rack and pinion actuator in the lock cylinder housing
• Insufficient lube on the actuator (do not apply lubricant to the inside of the ignition switch)
• Binding ignition switch

If the steering wheel lock is engaged with the wheels loaded against a curb, high effort will be necessary to turn the key from lock. Turn the steering wheel to either side of the lock to unload the system.

Carry out the following test to determine if the ignition switch and lock cylinder are operating correctly.

1. Inspect the ignition key for any burrs, damage or incorrect cut. Have a new ignition key made as necessary.

2. NOTE: The steering wheel may be locked full left or full right. If the steering wheel is locked, it will be necessary to apply turning effort to the steering wheel in the direction of the lock while turning the key.

   Turn the key to the ACC position and then the RUN position.
   • If the ignition key turns to the ACC and RUN position, continue with Step 3.
   • If the ignition key will not turn to the ACC and RUN position, continue with Step 4.

3. NOTE: The ignition switch and lock cylinder should return from the START position back to the RUN position without assistance.

   Turn the ignition key to the START position and release the key.
   • If the ignition switch and lock cylinder return from the START position back to the RUN position without assistance, the ignition switch is operating correctly at this time.
   • If the ignition switch and lock cylinder do not return from the START position back to the RUN position without assistance, continue with Step 4.

4. Remove the ignition lock cylinder. Refer to Section 501-14 .

5. Rotate the ignition lock cylinder through all of the switch positions.
   • If the lock cylinder operates correctly, continue with Step 6.
   • If the lock cylinder does not operate correctly, install a new ignition lock cylinder. Refer to Section 501-14 .

6. Check for binding or sticking ignition switch actuating rod, burrs around the rack-and-pinion actuator in the ignition lock cylinder housing or insufficient lubrication.
   • If there is sufficient lubrication and there are no burrs, binding or sticking conditions; install a new ignition switch. Refer to Ignition Switch in this section.
   • If there is insufficient lubrication, burrs, binding or sticking conditions; repair or lubricate as necessary.