U055A
Lost Communication With Windshield Wiper Control ModuleU055A is a generic OBD-II network diagnostic trouble code: Lost Communication With Windshield Wiper Control Module. It is logged by the engine control unit when the network monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What U055A means
U055A is set when the primary network controller loses all communication with the Windshield Wiper Control Module (WWCM). No messages from the WWCM are received within the expected interval, distinguishing this from an invalid-data fault where frames are present but contain bad content. Windshield wipers are a safety-relevant system, particularly for visibility in adverse weather conditions.
This code is classified at the lower end of severity for network faults because the wiper system typically operates on a low-speed LIN bus or a dedicated BCM sub-circuit rather than on the main powertrain CAN bus. Loss of the WWCM does not normally affect driveability, but it can render intermittent wipe, rain-sensing, and automatic wash/wipe inoperative, leaving only manual operation if the BCM retains a fallback path.
Common causes include a failed wiper control module, broken LIN bus wiring to the steering column or cowl area, and connector failures in areas exposed to water ingress near the windshield. Diagnosis should start with code retrieval, then move to power, ground, and bus continuity checks before replacing the module.
Common causes
Most-frequently reported root causes when U055A is logged.
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1
Failed or internally damaged Windshield Wiper Control Module.
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2
Open circuit in the LIN or CAN bus wiring to the WWCM.
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3
Loss of power or ground supply to the WWCM.
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4
Water intrusion into the WWCM connector or module housing near the cowl area.
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5
Corroded or backed-out connector pins at the wiper module.
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6
Damaged wiring harness in the steering column or cowl due to repeated flexing.
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7
Blown fuse supplying the WWCM circuit.
Symptoms drivers notice
How to diagnose U055A
A typical diagnostic flow when this code is present.
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1
Retrieve all stored DTCs and identify any companion bus or power-supply codes.
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2
Check the fuse for the WWCM circuit and inspect for blown condition.
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3
Verify power and ground at the WWCM connector with the ignition on.
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4
Inspect the wiring and connector in the cowl and steering column area for water damage or chafing.
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5
Test LIN or CAN bus continuity between the BCM and the WWCM connector.
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6
Clear codes and cycle the wiper stalk through all positions to check for intermittent return of communication.
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7
Replace the WWCM if wiring and power supply checks are within specification and no communication is restored.
Related network codes
- U0585 — Invalid Data Received From Active Grille Air Shutter Module "A"
- U0586 — Invalid Data Received From Active Grille Air Shutter Module "B"
- U058C — Invalid Data Received From Active Grille Air Shutter Module "C"
- U058D — Invalid Data Received From Active Grille Air Shutter Module "D"
- U0599 — Invalid Data Received From DC to DC Converter Control Module "A"
- U059B — Invalid Data Received From Hybrid/EV Battery Pack Sensor Module
Frequently asked questions
Can I drive with U055A active?
The vehicle is driveable but automatic and intermittent wiper functions may not work, which is a safety concern in rain or snow.
Is U055A related to the wiper motor itself?
Not directly. U055A points to the control module, not the motor; the motor itself may still operate if the BCM can energize the relay directly.
Why would water cause U055A?
The WWCM and its connectors are often located in the cowl area near the windshield base, which is a common water intrusion point during heavy rain or faulty sealing.
Could a blown fuse cause U055A?
Yes. A blown fuse removes power from the WWCM entirely, causing it to drop off the bus and triggering a lost-communication code.
Disabling U055A in software
RaceTune can permanently disable U055A — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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