Code
B2873
HUMMER
B — Body
Tilt Up Switch Circuit Malfunction
Views:
UK: 12
EN: 26
RU: 20
AI status
Completed
Completed
100%
Causes
- Faulty tilt-up switch
- Open or damaged wiring harness between switch and control module
- Short to ground or short to battery in switch circuit
- Corroded or loose connector terminals
- Blown fuse or failed relay supplying switch circuit
- Poor or missing ground
Symptoms
- Tilt-up function inoperative or intermittent
- DTC B2873 stored in the BCM or instrument cluster memory
- Related switch may have no tactile feedback or feel sticky
- Other body convenience functions may behave erratically if the BCM is affected
- Possible warning lamp or message on instrument cluster
What to check
- Retrieve freeze frame and full DTC list with a capable scan tool; note occurrence conditions
- Visually inspect tilt-up switch, bezel and surrounding area for damage, water, or contamination
- Inspect switch connector and mating connector at module for corrosion, bent pins, or loose terminals
- Check related fuse(s) and relays for the tilt/roof/seat circuit
- Wiggle harness while operating the switch to reproduce intermittent behavior
- Review wiring diagram to identify power, ground, and signal paths and connector locations
Signal parameters
- Reference/supply voltage typically ~12 V with ignition ON (verify on vehicle)
- Switch signal when actuated may be near battery voltage or pulled to ground depending on design — expected transition between ~0 V and ~12 V
- Open circuit shows no continuity between switch terminal and module input (infinite Ω)
- Closed switch continuity should be low (typically
- Module input may be a high-impedance sense (verify with wiring diagram)
Diagnostic algorithm
- Verify the code with a scan tool and note freeze-frame data. Clear codes and attempt to operate the tilt-up function to re-check. 2) Perform a visual inspection of the switch assembly and harness for damage, contamination, or water ingress. 3) Inspect and secure all related connectors; unplug and check pins for corrosion or damage. 4) Check fuses/relays that supply the switch circuit; replace if blown or faulty. 5) With ignition ON, back-probe the switch connector and measure supply/reference voltage and signal voltage in each switch position; compare to expected values from the wiring diagram. 6) Check continuity between the switch signal terminal and the receiving module terminal; repair any open circuits. 7) Check for shorts to ground or battery: isolate the circuit and measure for unexpected continuity to ground or battery. 8) Wiggle test harness while monitoring signal to reproduce intermittent faults. 9) If switch wiring and connectors test good, test or replace the tilt-up switch. 10) If the fault persists after switch replacement, test the module input/output and grounds; replace or reprogram the BCM or the responsible control module only after confirming wiring integrity. 11) After repairs, clear codes and verify proper operation over multiple cycles. 12) Refer to manufacturer wiring diagrams and follow any specific service procedures or calibrations required after component replacement.
Likely causes
- Failed or dirty tilt-up switch contacts
- Damaged pin or broken wire in the door/console harness near the switch
- Connector corrosion at the switch or at the BCM/pigtail
- Short to battery from chafed insulation where wiring flexes
- Intermittent ground at module or chassis ground point
Fault status
Status
Tilt Up Switch circuit malfunction detected (open/short/invalid signal). Check switch, wiring, connectors, fuses, and module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Repair manuals
Manual library for HUMMER
138
Browse 138 HUMMER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
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