B29D5

Code

Generic B — Body

Loss of Communication with Driver Door Module

Brand: Generic

Type: B — Body

Views: UK: 8 EN: 7 RU: 5

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or disconnected wiring/connector between DDM and network/BCM
Blown fuse or failed power/ground for the DDM
Corroded or bent connector pins at the door hinge harness
Faulty driver door module
Fault on the vehicle communication bus (CAN/LIN) such as short, open, or missing termination
Software or configuration mismatch after module replacement or update

Symptoms

Power window(s), mirror, or door lock functions for driver door inoperative or intermittent
Driver door unlock/lock from remote/keyless may not work
Message center warnings about door module or communication fault
Some convenience features (auto up/down, puddle light) not working
Stored communication-related DTC(s) and possible network-related DTCs

What to check

Connect a scan tool and confirm B29D5 plus any related codes or freeze frame data
Verify battery voltage is within specification (engine off and on) before testing
Inspect fuses/relays that feed the driver door module for continuity and correct rating
Visually inspect door hinge harness and connector for chafing, corrosion, or broken wires
Attempt to communicate with the DDM using a scan tool; note if communication is intermittent
Wiggle test the door harness and connectors while monitoring bus traffic and DDM communication

Signal parameters

Module supply voltage (with ignition on): ~11–14 V expected
Ground: low resistance to chassis (
High-speed CAN idle (recessive): CANH ≈ 2.5 V, CANL ≈ 2.5 V; dominant state: CANH ≈ 3.5 V, CANL ≈ 1.5 V (verify with vehicle spec)
Low-speed CAN/LIN nodes: refer to vehicle-specific idle voltages; LIN idle near battery via pull-up (varies)
Termination resistance for high-speed CAN: ~60 ohm measured across CANH–CANL at network ends (two 120 Ω in parallel)
Typical module communication interval: periodic messages at defined rates — absent or irregular messages indicate failure

Diagnostic algorithm

Verify the code with a competent scan tool and record all stored/active DTCs and freeze frame data.
Check battery voltage and charging system; ensure steady system voltage during testing.
Inspect fuses and relays for the DDM circuit; replace any suspect fuses and re-check communication.
Visually inspect the driver door harness from the door to the body connector and to the BCM for damage, pin corrosion, or rodent chew.
With the scan tool connected, attempt communication with the DDM. Wiggle the harness and connectors while observing for intermittent connection or changes.
Measure power and ground at the DDM connector. Repair any open/low-voltage or high-resistance ground conditions.
Check network signals (CAN/LIN) at the DDM and at a known-good module: verify idle voltages, presence of differential signals, and termination. Use an oscilloscope if available for bus waveform analysis.
If bus fault suspected, isolate sections of the network (disconnect modules or short segments) to locate a short/open. Repair wiring faults found.
If wiring and bus are good but DDM still does not respond, check for available software updates or reprogramming procedures required for the module. Clear codes and attempt relearn or module wake-up per service information.
If module remains non-communicative after all tests, consider replacing the DDM. After replacement, program/configure the new module as required and confirm normal communication and function.
Note: avoid repeated power-cycling and always follow vehicle-specific safety and programming procedures.

Likely causes

Broken/damaged wiring in the door jamb harness (most common)
Loose or corroded connector pin at the DDM or BCM
Failure of the DDM (internal fault)
Blown fuse supplying DDM power
Vehicle network wiring shorted to ground or battery

Fault status

⚠️ Status

Loss of Communication With Driver Door Module — the driver door module is not responding on the vehicle communication network (CAN/LIN). This may be intermittent or continuous and can disable door-related features.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3.0 hours