B2704

Code

HUMMER B — Body

Ignition Shift Interlock Circuit Open

Brand: HUMMER

Type: B — Body

Views: UK: 10 EN: 13 RU: 13

AI status

Completed

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Page language: EN

Causes

Broken or open wiring between BCM, ignition switch and shift interlock solenoid
Corroded/damaged connector at shift interlock solenoid or BCM
Blown fuse or fusible link protecting the circuit
Failed shift interlock solenoid or actuator
Faulty ignition switch or key cylinder switch
Body control module (BCM) internal fault or loose BCM connector

Symptoms

Cannot shift out of Park (shift lock engaged)
Key may be stuck in the ignition or cannot be removed
Shift interlock light or dashboard message related to shift/parking
No clicking or actuation noise from the shift interlock when turning key
Possible other body electrical oddities if BCM affected

What to check

Verify customer complaint and attempt to reproduce symptom
Scan vehicle for stored codes and related data using a capable scan tool
Inspect fuses and fusible links for the interlock circuit
Visually inspect connectors at the shift interlock solenoid, ignition switch, and BCM for corrosion, damage, or poor seating
Check battery voltage and main power feeds to BCM and ignition circuits
Listen for solenoid operation when key is turned (or use a test light/voltmeter)

Signal parameters

Nominal battery supply: ~12 V at solenoid power feed with key ON or during release command
Control signal: switched battery or ground depending on vehicle design (verify with wiring diagram)
Expected solenoid current draw typically low (hundreds of mA); large deviations indicate short or open
At rest: continuity expected between solenoid power and BCM driver when commanded; open when not commanded (verify per wiring diagram)
Ground reference should be

Diagnostic algorithm

Confirm symptom and note when code set (conditions: key position, battery voltage, attempted gear selection).
Retrieve freeze frame/vehicle data from scan tool and check for related codes (ignition, BCM, CAN bus).
Visually inspect wiring/connectors at shift interlock solenoid, ignition switch, instrument panel and BCM. Repair obvious damage and reseat connectors.
Check relevant fuses and fusible links; replace if blown and retest. If fuse blows again, suspect short.
With ignition OFF and battery disconnected, perform continuity check from the solenoid connector to the BCM connector and to ground to identify open circuit. Repair any open or high-resistance wiring.
With battery connected, backprobe solenoid connector while operating ignition/attempting to shift. Verify presence of battery voltage or switching ground when command is given. Compare to signal parameters.
Bench-test or apply 12 V directly to the solenoid (with proper safety precautions) to confirm it actuates. Replace solenoid if it does not operate.
Check ignition switch outputs (key position sensing) for expected signals to BCM when turning key; repair/replace ignition switch if faulty.
If wiring and components test good, check BCM outputs/drivers with scope or DVOM as appropriate. If BCM output is missing and wiring confirmed good, consider BCM repair/replacement following manufacturer procedures.
After repair, clear codes, operate vehicle through several key cycles and drive cycles to verify repair. Re-scan for codes and confirm normal operation of shift interlock.

Likely causes

Open or damaged wiring/connectors to the shift interlock solenoid
Failed/shorted shift interlock solenoid
Blown fuse or poor power supply to the circuit
Faulty ignition switch not providing enable signal
Loose/poor BCM connector or BCM internal failure

Fault status

⚠️ Status

Open circuit detected in the ignition shift interlock circuit. The body control module has detected loss of continuity or missing command/feedback for the shift interlock device, which can prevent the shifter from releasing out of Park.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5 - 2 hours

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