U046D: Invalid Data Received From Fuel Pump Control Module B

What it means

A receiving module detected implausible data from fuel pump control module B. Pressure, duty cycle or current values fail plausibility checks and are rejected; engine fueling may be limited.

At a glance

• Usually lights the warning light of the system that lost communication
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

Fuel pump control module B controls or monitors the vehicle's second designated fuel-pump circuit or pump, where fitted, and reports values such as pressure, duty cycle, or current. A receiving module sets U046D when those reported values fail plausibility checks and are rejected, which can limit engine fueling.

Common causes

Most likely first.

1. Module internal fault or sensor input drift
2. Software version mismatch after replacement
3. Gateway module routing CAN messages incorrectly

Symptoms

• Multiple warning lights may illuminate
• Affected modules may go into limp mode or shut down
• Specific functions inoperative depending on module
• Diagnostic tools may show communication faults

How to diagnose it

1. Scan all modules and save freeze-frame data, fuel-pressure codes, and communication faults to identify when module B's data was rejected.
2. Compare live pressure, duty-cycle, and current data for fuel pump control module B with engine demand and any available readings for the other pump circuit.
3. Inspect module B's connectors, wiring, grounds, and fuse connections for corrosion, heat damage, loose terminals, or chafing.
4. Check the CAN network and gateway for faults affecting module B, then verify pump operation and pressure using the manufacturer's procedure.
5. If power, wiring, and network checks pass, test module B's sensor inputs and software compatibility before condemning the pump or control module.

Common fixes

• Repair a loose, corroded, or damaged module B connector or harness.
• Correct a poor power or ground connection or a failed fuse connection.
• Repair the module B pressure-sensing or pump-control circuit if testing identifies the fault.
• Update or configure a replacement fuel pump control module B.
• Replace a faulty pump or module B only after pressure, current, and control checks confirm it.

Can I keep driving?

Avoid driving if the engine is stumbling, losing power, or entering limp mode, since fuel delivery may become insufficient or the engine may stall. If symptoms are mild, keep trips short and avoid heavy acceleration until the fault is diagnosed.