B2357 – Lost communication with wiper module (Toyota)

Toyota-specific code — factory diagnostic data

B2357 means the Toyota Corolla lost communication with the wiper module, so the wipers may act up or stop working. You may also lose some automatic wiper features, depending on the platform. According to Toyota factory diagnostic data, this is a manufacturer-specific body DTC that indicates “Lost communication with wiper module.” In plain terms, the main body module expected to “hear from” the wiper module but did not. That points you toward a network, power, ground, or module wake-up issue first. It does not prove the wiper motor or module failed.

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B2357 Quick Answer

The main body module stopped receiving wiper module messages. Diagnose power, ground, and the communication network to the wiper module before replacing parts.

What Does B2357 Mean?

Official definition: “Lost communication with wiper module.” What the module detected: the main body module did not receive expected communication from the wiper module for a certain time. What that means in practice: the vehicle may lose wiper operation, lose intermittent control, or show erratic wiper behavior because body systems cannot coordinate with the wiper control unit.

What the module is actually checking: the main body module monitors network message presence, timing, and plausibility from the wiper module. It sets B2357 when those messages stop, drop out, or never start after a wake-up event. Why that matters for diagnosis: communication loss usually comes from a power/ground dropout, harness damage, connector pin fit, network line faults, or a module that stays asleep. Start with circuit integrity and network health. Do not start with motor or module replacement.

Theory of Operation

On Toyota vehicles, the main body module coordinates body functions and network communication. The wiper module handles wiper requests and motor control logic. It also reports status back to the network. When you move the wiper stalk or when the vehicle wakes up, the wiper module should power up and exchange messages with the main body module.

B2357 sets when that message exchange stops. A wiper module can drop off the network if it loses battery power, loses ground under load, or fails to wake. A shorted network line can also block traffic and make the wiper module “disappear.” An intermittent connector at the wiper module often causes a repeatable failure during bumps, moisture, or temperature changes.

Symptoms

Communication-loss codes usually show up first on a scan tool, then as body-function complaints.

• Scan tool Wiper module does not respond, shows “no communication,” or drops out intermittently during a health check
• Wipers inoperative Front wipers do not run in any switch position
• Intermittent function Intermittent speed stops working or behaves erratically
• Auto wipe Automatic wipe feature becomes unavailable or inconsistent (if equipped)
• Park position Wipers stop mid-sweep or fail to park correctly
• Related DTCs Additional body or network codes store with B2357, often after low voltage events
• Condition changes Symptoms worsen with vibration, steering column movement, or after rain washing

Common Causes

• Wiper module power feed interruption: A blown fuse, weak relay contact, or open power feed prevents the wiper module from booting, so the Main Body cannot exchange messages.
• High-resistance ground at the wiper module: Corrosion or a loose ground bolt lets the module power up partially, then drop offline when the motor or internal drivers load the circuit.
• Open or high resistance in the communication harness: A stretched, pinched, or partially broken wire in the body harness stops message traffic and triggers a “lost communication” decision in the Main Body.
• Short to ground or short to power on the communication line: A rubbed-through wire can pull the network line low or high and block all valid data frames from the wiper module.
• Connector terminal damage or poor pin fit: Spread terminals, backed-out pins, or moisture in the connector create intermittent contact that drops the wiper module off the network.
• Incorrect battery support during service: Low system voltage during cranking, jump starts, or battery replacement can reset modules and expose marginal power, ground, or network integrity.
• Aftermarket electrical add-ons near the steering column or cowl: Added loads or splices can introduce noise, poor grounds, or harness damage that interrupts Toyota body network communication.
• Wiper module internal fault: Internal power supply failure or circuit board damage can stop communication, but confirm the external circuits first.

Diagnosis Steps

Use a scan tool that can run a Toyota body network scan and display Main Body data. You also need a DMM, a fused test light, and back-probe pins. For harness checks, keep wiring diagrams and connector views available. Plan to perform voltage-drop tests under load, not continuity checks alone.

1. Confirm B2357 in the Main Body and record DTC status (pending vs stored). Save freeze frame data, especially ignition state, vehicle speed, system voltage, and any related body or wiper DTCs. Freeze frame shows conditions when the fault set. Use a scan tool snapshot later to capture an intermittent dropout during a wiggle test or road test.
2. Run a full network scan and note whether the wiper module appears as an online ECU. If the scan tool cannot “see” it, treat the issue as a hard offline module or network/power problem. If it appears online, focus on intermittent communication loss and connector fit.
3. Check power distribution first. Inspect the wiper-related fuses and any body/ECU fuses that feed the wiper module or Main Body. Do not stop at a visual check. Verify power on both sides of each fuse with ignition ON and the circuit commanded active.
4. Command the wipers with the scan tool, if supported, or operate them with the switch. Watch for wiper module data PIDs and network status changes. A module that drops offline under load often points to a power or ground voltage-drop problem.
5. Verify the wiper module power feed under load. Back-probe the module power terminal and measure voltage while the wipers operate or while you load the circuit with a fused test light. A good circuit holds near battery voltage. A large drop indicates resistance in the fuse, relay, splice, or harness.
6. Voltage-drop test the wiper module ground under load. Keep the circuit operating and measure from the module ground pin to battery negative. Accept less than 0.1V drop with the circuit active. If you see more, clean and tighten the ground point and inspect the ground splice.
7. Inspect connectors and harness routing at the wiper module, Main Body, and any in-line connectors along the cowl and dash harness. Look for water tracks, green corrosion, bent pins, backed-out terminals, and poor pin tension. Correct terminal fit problems before replacing any module.
8. Check communication circuit integrity with ignition ON. Measure the communication line(s) to ground at an accessible connector while the network remains powered. Do not use ignition-OFF readings as a reference. Compare to expected biased network behavior per Toyota service information, and look for a stuck-high or stuck-low condition that matches a short.
9. If the wiper module stays offline and the platform uses CAN for this link, isolate the bus. Turn ignition OFF, disconnect the battery, and measure resistance between CAN+ and CAN- at an accessible connector. Healthy networks read about 60 ohms. Readings near 120 ohms or OL suggest an open or missing termination. A very low reading suggests a short.
10. Perform a controlled wiggle test. Keep ignition ON, monitor the wiper module online status and related PIDs, and gently flex the harness and connectors at known stress points. Capture a scan tool snapshot when the dropout occurs. This helps you pinpoint the exact harness section that fails.
11. After repairs, clear codes and retest under the same conditions shown in freeze frame. Confirm the wiper module stays online during repeated wipe commands, key cycles, and a short drive. Re-scan the network to confirm B2357 does not return as pending or stored.

Professional tip: Do not trust continuity checks on network wiring. A single corroded strand can pass a continuity beep and still fail under vibration. Load the power and ground circuits, then watch the scan tool network list while you move the harness. That combination finds the real dropout point fast.

Possible Fixes

• Repair the wiper module power feed fault: Replace the blown fuse only after you locate the overload or short, and repair any high-resistance power-side connector or splice.
• Restore a clean, low-resistance ground: Clean the ground eyelet and body contact, tighten the fastener, and repair damaged ground wiring to achieve a low voltage drop under load.
• Repair communication wiring damage: Fix opens, shorts, and chafed sections, then restore correct routing and protection to prevent repeat failures.
• Service connector terminals: Remove corrosion, correct backed-out pins, and replace terminals that lost tension or show heat damage.
• Correct aftermarket wiring issues: Remove improper splices, restore factory wiring, and relocate added accessories away from body network harness runs.
• Replace the wiper module only after circuit proof: If power, ground, and communication circuits test good and the module still stays offline, replace and initialize it per Toyota procedures.

Can I Still Drive With B2357?

You can usually drive a Toyota Corolla with B2357, but you should treat the wipers as unreliable. This DTC means the main body module lost communication with the wiper module. If the network drops out, the wipers may park wrong, run in one speed only, stop mid-sweep, or ignore washer commands. Rain, road spray, and night glare turn this into a visibility and safety problem fast. Do not plan a long drive in bad weather until you confirm stable wiper operation. If the wipers fail during your test drive, stop and repair the fault before using the car in wet conditions.

How Serious Is This Code?

B2357 ranges from an inconvenience to a real safety issue. In dry conditions, you may only notice a warning message, intermittent wiper behavior, or stored history codes. In wet weather, this becomes serious because you can lose windshield clearing at speed. The fault does not usually affect engine drivability, but it can indicate a broader body network problem. A shorted harness, water intrusion, or a weak power or ground feed can drag down communication and trigger other body DTCs. Treat the code as high priority if the wipers act up, if multiple communication codes set, or if the code resets immediately after clearing.

Common Misdiagnoses

Technicians often replace the wiper motor or wiper module first, then discover the network fault remains. B2357 points to a lost-communication condition, not a confirmed failed actuator. Another common mistake involves checking power and ground with no load. A corroded ground can look “good” on a meter yet fail under wiper load. Shops also miss connector fit issues at the cowl area after windshield or body work. DIY owners often blame the wiper switch without verifying the main body module can see switch requests. Avoid wasted parts by confirming scan-tool communication, checking related network DTCs, and performing voltage-drop tests under load.

Most Likely Fix

The most frequently confirmed repair path starts with wiring integrity, not module replacement. Many B2357 cases trace to poor power or ground to the wiper module, water intrusion at connectors, or harness damage near the cowl where the wiper system lives. A second common direction involves restoring network integrity on the body communication lines between the main body module and the wiper module. Only after you confirm stable power, ground, and network signals should you consider a wiper module fault. If a module replacement becomes necessary, Toyota vehicles commonly require Techstream for configuration, initialization, or registration steps.

Repair Costs

Network and communication fault repairs vary by root cause — wiring/connectors are often the source, but module-level repairs or replacements can be significantly more expensive.

Last updated: April 10, 2026

Definition source: Toyota factory description · Autel MaxiSys Ultra & EV. Diagnostic guidance is based on factory-defined fault logic for this code.