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Home / DTC / U0296 — Lost communication with the AC and DC converter control module A

U0296 — Lost communication with the AC and DC converter control module A

Detailed page for trouble code U0296.

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11,689generic
22,491specific
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Code

U0296

LAND ROVER U — Network/User

Lost communication with the AC and DC converter control module A

Brand: LAND ROVER
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty AC/DC converter control module (module A) or internal failure
  • CAN bus wiring fault (open, short to battery, short to ground)
  • Poor connector contact, corrosion, or damaged pins at the module or junctions
  • Power or ground supply to the module missing or intermittent (fuse, relay, battery)
  • Network termination or bus voltage problems (missing termination resistor, bus short)
  • Software/configuration mismatch or module not programmed/provisioned

Symptoms

  • MIL/Warning lamp illuminated (hybrid/EV or general warning)
  • Reduced charging or loss of DC‑DC conversion functions
  • Reduced traction or limp‑in mode if inverter functions affected
  • Associated modules report communication errors or fallback behavior
  • Inoperative HVAC blower or 12V accessory issues if DC‑DC is offline

What to check

  • Read all stored codes and freeze frame data with a compatible diagnostic tool; note if code is permanent or intermittent
  • Verify vehicle battery voltage (12V) and state; check main fuses and relays for the converter/control module
  • Visual inspection of module connector for corrosion, bent pins, water ingress, or damage
  • Check for presence of the module on the network with diagnostic tool (module present/identified?)
  • Scan other modules for network communication issues on the same CAN bus
  • Measure CAN_H and CAN_L voltages at the module connector with key ON, engine off

Signal parameters

  • CAN bus recessive voltage: both CAN_H and CAN_L ≈ 2.5 V
  • CAN bus dominant state: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2 V)
  • Normal idle differential voltage ≈ 0 V (lines equal near 2.5 V); active messages produce differential pulses
  • Module supply: vehicle nominal battery voltage (about 12–14 V with ignition on) on its +B terminal
  • Module ground: low resistance to chassis ground (< 1 ohm typical)

Diagnostic algorithm

  1. Connect a capable scan tool, read all codes and data. Confirm U0296 occurrence and note time/ignition state.
  2. Attempt to communicate with the AC/DC converter control module using the tool. If the module responds, clear codes and re-test to reproduce.
  3. Check battery voltage and main fuses/relays feeding the module. Replace blown fuses and retest communications.
  4. Visually inspect the module connector and wiring. Disconnect connector, inspect pins for corrosion, damage, or pushed out terminals. Reconnect securely.
  5. With ignition ON (engine off), measure CAN_H and CAN_L at the module connector. Verify recessive voltages ~2.5 V and correct dominant/idle behavior using a scope if available.
  6. If CAN bus voltages are incorrect, isolate the bus: unplug adjacent modules or junctions to find short or open section. Check termination resistors (~60 ohm across CAN_H/CAN_L at network ends).
  7. If bus and power/ground are good but module still not responding, try software/firmware checks: confirm module programming and network configuration with manufacturer-level tool; update or reprogram if advised.
  8. For intermittent faults, perform wiggle tests on harness and connectors while monitoring communication to reproduce interruption. Use backprobing and scope for transient faults.
  9. If module is confirmed dead (no power/ground/CAN response and wiring verified), replace the AC/DC converter control module A and program/configure as required. Clear codes and verify system operation.
  10. After repair, road test and re-scan to confirm no recurrence and that associated systems function normally.

Likely causes

  • Lost power or ground to the AC/DC converter control module A (fuse, relay, connector)
  • Faulty or disconnected CAN_H/CAN_L at the module (open or short)
  • Corroded or loose module connector pins
  • Failed AC/DC converter control module

Fault status

⚠️ Status
U0296 — Lost communication with AC and DC converter control module A. Stored when module does not respond on the CAN network within the expected timeout or when the network receives invalid/no messages from that module. May be intermittent or permanent depending on cause.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

U0100 U0121 U0140 U0297
320

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