U0446

Code

Generic U — Network/User

Invalid Data Received From Body Control Module E

Brand: Generic

Type: U — Network/User

Views: UK: 27 EN: 56 RU: 30

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Faulty or misprogrammed Body Control Module E (BCM E)
Corroded, loose, damaged, or water-intruded connectors or wiring to BCM E
Low battery voltage, poor battery connection, or weak charging system
CAN/LIN bus physical-layer faults (shorts, opens, missing termination, high resistance)
Intermittent ground or power to BCM E or other network modules
Software mismatch or corrupt calibration between modules after service or update

Warning or communication fault indicator on cluster (CAN/network warnings)
Loss or intermittent operation of functions controlled by BCM E (doors, interior lights, remote entry, body features)
Stored communication DTCs in other modules referencing BCM E
No-start or limp features if BCM E provides critical inputs
Multiple modules show related or cascading communication errors

Use a diagnostic scanner to read all current and historic U-codes and BCM E specific DTCs and freeze frame data
Verify battery voltage and charging system at rest and cranking (12.4–12.8 V resting, >13.5 V running)
Visually inspect BCM E connector and harness for corrosion, bent pins, water ingress, or physical damage
Scan CAN bus for errors and check status of other modules (which modules can/cannot communicate)
Measure CAN_H/CAN_L voltages with multimeter and view waveforms with an oscilloscope or CAN bus analyzer
Check CAN termination resistance across H and L (approx. 60 ohms for two 120 ohm terminators in parallel)

Typical CAN idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (recessive). Dominant state: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V; differential ≈ 2 V
Termination: ~60 ohms measured across CAN_H and CAN_L at diagnostic connector (two 120 Ω terminators in parallel)
Common bus speeds: 250 kb/s or 500 kb/s (vehicle-specific)
Expected message timing: periodic message cycle times vary by vehicle and module (verify against OEM data)
Message length: valid CAN frames must match expected ID and payload length for BCM E messages (check frame ID and data contents with a CAN sniffer)

Capture DTCs and freeze frame with a manufacturer-level scan tool. Note which modules report communication issues and timestamps.
Inspect BCM E connectors and wiring for corrosion, damage, or moisture. Repair or clean as needed.
Verify battery negative and positive connections and measure system voltage under load; resolve low-voltage or charging issues.
With key on (engine off), measure CAN_H/CAN_L voltages at the diagnostic connector and at the BCM E connector; compare to expected values.
Use an oscilloscope or CAN analyzer to observe frames on the bus. Look for corrupted frames, bus errors, or unexpected IDs from BCM E.
If bus errors or corrupted frames appear, isolate by disconnecting non-critical modules (one at a time) and rechecking bus health to find a contributor.
Perform a wiggle test of harness sections while monitoring live data to reproduce intermittent faults.
Check for software/calibration updates or module configuration mismatches. Reflash or reprogram BCM E only after confirming hardware and bus integrity.
If BCM E is proven defective (consistent invalid outputs, self diagnostics, internal faults), replace and program per OEM procedures.
After repair, clear DTCs and road-test while monitoring network messages to confirm the fault does not return.

Poor connector mating or pin corrosion at BCM E
Damaged CAN pair near BCM E (chafed wiring, rodent chew, pinched harness)
Failed BCM E internal hardware or memory corruption after an update
Missing/failed termination resistor or excessive bus load near BCM E
Intermittent vehicle voltage (weak battery, poor alternator or cables) affecting module operation