Code
B1874
Other
B — Body
Cellular Phone Handset Not Present
AI status
Completed
Completed
100%
Causes
- Handset not powered on, not seated, or removed from cradle
- Bluetooth/pairing link not established or lost
- Damaged or disconnected handset/cradle connector or wiring
- Blown fuse or lost power/ground to handset or cradle
- Faulty handset, cradle assembly, or hands‑free telematics module
- Software/firmware mismatch or configuration error
Symptoms
- Message or indicator: 'Cellular Phone Handset Not Present' or similar
- No hands‑free calling or audio routing to vehicle
- Phone functions in vehicle disabled or missing phone icon/menu
- Intermittent phone connection, dropouts during calls
- Scan tool shows B1874 stored in telematics/hands‑free module
What to check
- Confirm customer description: is the handset present, powered on, and seated correctly?
- Check Bluetooth or pairing status on both phone and vehicle interface
- Use a scan tool to read all related codes from telematics, BCM, and infotainment modules
- Inspect handset/cradle connectors and wiring for damage, corrosion, or loose pins
- Verify continuity to ground and supply voltage at the handset/cradle connector
- Check relevant fuses and relays for the hands‑free/telematics circuits
Signal parameters
- Handset presence/detect signal (digital input to telematics module)
- 12V supply voltage and ground at handset/cradle connector
- Bluetooth connection status / link layer status (paired/connected)
- CAN bus or LIN messages between telematics/hands‑free and BCM
- RSSI or Bluetooth signal quality when handset in position
- Handset cradle switch status or proximity sensor reading
Diagnostic algorithm
- Verify complaint and reproduce: confirm handset is/was present and check displayed message.
- Check for related DTCs with a capable scan tool in telematics/infotainment and BCM. Record freeze frame if available.
- Ask operator to remove and re‑seat handset in cradle; power cycle the handset and vehicle system; attempt re‑pairing via vehicle Bluetooth menu.
- Inspect the physical cradle and handset for damage, corrosion, or foreign objects preventing proper seating or contact.
- With vehicle off, inspect fuses and measure supply voltage and ground at the handset/cradle connector with a multimeter. Repair wiring or replace fuse as needed.
- Verify continuity and pin condition between handset connector and telematics module; repair any damaged harness sections or connectors.
- If wiring and handset appear OK, update or reflash telematics/infotainment software per manufacturer service information, then clear codes and retest.
- If problem persists and all wiring/software verified, swap or replace the handset/cradle assembly (if removable) or replace the telematics/hands‑free module as directed by service procedures.
- After repairs, clear DTCs and perform functional test: confirm handset presence detection and complete hands‑free call tests.
- Safety note: isolate power before connector repairs. Follow OEM procedures for module programming and radio frequency device handling.
Likely causes
- User left phone off or out of vehicle/cradle
- Phone not paired or pairing corrupted after a battery change or phone update
- Loose connector at handset cradle or corroded contacts
- Blown fuse supplying the hands‑free or handset circuit
- Failed handset detection switch or sensor in the cradle
- Vehicle module software needs update or reset
Fault status
Status
Handset presence not detected by vehicle telematics/hands‑free module — no presence/pairing signal received from cellular handset or cradle.
Repair difficulty: Medium
Diagnostic time: 0.5 - 2.0 hours
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