B116A

Code

Generic B — Body

Passenger Seat Module Communication Fault

Brand: Generic

Type: B — Body

Views: UK: 15 EN: 30 RU: 20

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Page language: EN

Passenger seat functions (power adjustment, heating, memory) inoperative or intermittent
Seatbelt/occupant detection or airbag system warnings (passenger side)
Related dash warning lamp or message for passenger restraint/seat module
Stored B116A and potentially other network communication codes
Other modules reporting 'no response' for PSM or showing unavailable data

Retrieve freeze frame, full DTC list and module presence with a capable scan tool
Check for related U- and B- codes on main network (CAN/LIN) indicating bus issues
Inspect fuses and relay circuits that supply the passenger seat module
Visually inspect seat wiring harness, connectors, and routing under the seat for damage or corrosion
Confirm module retains correct supply voltage (battery ~11–14.5 V) and good ground (near 0 V)
Check CAN/LIN bus voltage levels at seat module connector with scope or multimeter

Battery supply to module: ~11–14.5 V with ignition on
Module ground: ~0 V (low resistance to chassis ground)
CAN bus idle voltages: CANH ≈ 2.5 V, CANL ≈ 2.5 V; dominant state: CANH ≈ 3.5 V, CANL ≈ 1.5 V (typical)
LIN bus idle: single wire ≈ battery voltage or pulled low when active depending on design
Termination: two 120 Ω resistors in parallel = ~60 Ω across CANH and CANL

Connect a diagnostic scanner; read and record all DTCs, freeze frame data, and module presence. Note time of occurrence and related codes.
Clear codes and attempt to reproduce. If code returns, proceed with physical checks.
Verify fuses and ignition-switched power to the PSM. Check for correct voltage at the module power pin(s).
Verify good ground(s) at the module connector and continuity to chassis ground.
Inspect and test seat wiring harness and connector for corrosion, broken wires, pin damage, or water ingress. Pay attention to wires routed through seat rails.
Check communication bus: measure CANH/CANL (or LIN) at the module connector with engine on/ignition on and while exercising related functions. Confirm proper idle voltages and termination resistance (~60 Ω).
Perform wiggle test of connectors and wiring while monitoring bus and scan tool for loss of communication or intermittent codes.
If bus is dead or noisy, isolate segments: disconnect nearby modules to find fault location, or use a scope to identify noise/transients.
If wiring and power/ground are good and bus is healthy, check module software/version and reflash/update per manufacturer procedure. Reprogram or configure module if required.
Replace the passenger seat module only after verifying fault persists and replacement is supported. After replacement, program/configure and confirm normal operation and no recurring codes.
Document repair and clear codes, then road-test and re-scan to ensure the fault does not return.