U0131 – Lost communication with power steering control module A missing message

Last updated: April 11, 2026

U0131 means the vehicle lost communication with the power steering control module A. In plain English, the steering warning light may turn on, steering assist may change, and a scan tool may not talk to the steering module. According to factory-style diagnostic data used across many brands, this code indicates a missing message on the vehicle network, not a confirmed failed steering module. The U0131 code points to a communication loss in the network system. You must verify module power, ground, connector condition, and network integrity before you replace any part, because the exact module location and network path vary by make, model, and year.

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U0131 Quick Answer

U0131 means another module stopped receiving expected messages from the power steering control module A. Check whether the steering module appears on a full network scan first, then test its power, ground, and communication circuits.

What Does U0131 Mean?

The official U0131 meaning is lost communication with power steering control module A missing message. That means one or more control modules expected data from the steering control module and did not receive it. In real use, the driver may see a steering warning, reduced assist, or no obvious steering complaint at all. The code identifies a network communication problem area, not a confirmed bad module.

Technically, a module on the vehicle network monitors expected message traffic and timing. When the expected steering-related message never arrives, or drops out long enough to fail the module’s internal logic, it sets U0131. With the SAE J2012DA FTB suffix -87, this points to a highly diagnostic missing message condition. Treat it like a no-signal communication loss. Do not assume the module failed. A power feed problem, ground loss, connector issue, or network wiring fault can create the same code.

Theory of Operation

Under normal conditions, the power steering control module A exchanges data with other modules over the network. The exact bus can vary by platform. On many vehicles, the steering module sends status, torque-assist information, fault status, and operating state to the ABS, PCM, BCM, or gateway. Those modules use that data for steering assist strategy, warning lamp control, stability functions, and system plausibility checks.

U0131 sets when that message flow stops. The fault can occur because the steering module loses power, loses ground, resets, or drops off the network. It can also occur when the communication pair opens, shorts, or gets pulled down by corrosion or water intrusion. On some vehicles, a gateway module routes traffic between network segments. In that case, the steering module may still work locally while another module logs U0131 because the message never crosses the network path.

Symptoms

U0131 symptoms depend on how the vehicle shares steering data, but several patterns show up often.

• Scan tool issue: The power steering control module A does not appear on the module list, will not communicate, or drops offline intermittently during a network scan.
• Steering warning: A power steering, EPS, or steering assist warning light turns on in the cluster.
• Changed steering assist: Steering effort becomes heavier than normal, especially at low speed, or assist may switch to a backup mode.
• Stored network codes: Other modules store U-codes because they depend on steering module messages for shared system operation.
• Intermittent steering complaint: Assist may return after a key cycle, then fail again when vibration, heat, or moisture affects the circuit.
• Related stability warnings: Traction control, ABS, or stability indicators may illuminate if those systems cannot validate steering-related data.
• No obvious drivability issue: Some vehicles drive normally except for warning lamps and stored U0131 code data.

Common Causes

• Loss of power steering control module power feed: A blown fuse, weak relay, or open B+ circuit can shut the module down so it stops transmitting its required network message.
• High-resistance or open module ground: Corrosion, a loose ground eyelet, or damaged ground wire can let the module wake up poorly or reset, which creates a lost communication condition.
• CAN bus open circuit: An open in CAN high or CAN low interrupts message flow between modules, so other controllers log U0131 when they no longer hear from the power steering control module.
• CAN bus short to ground, short to voltage, or shorted pair: A network short distorts bus bias voltage and blocks normal data traffic, which can take the steering module offline even if the module itself still has power.
• Connector corrosion or terminal spread at the steering module: Poor terminal tension or moisture intrusion adds resistance at the module connector and can interrupt power, ground, or network circuits intermittently.
• Harness damage near steering gear, column, or front subframe: Flexing, road debris, and previous repairs often damage the wiring near moving or exposed steering components, which can break communication circuits.
• Low system voltage or unstable charging voltage: A weak battery or charging fault can cause the steering module to brown out during cranking or low-speed maneuvers, leading to missing CAN messages.
• Network fault in another module or splice pack: A shorted controller elsewhere on the same bus, or a failed network junction, can pull the whole communication line down and trigger U0131.
• Incorrect module programming or configuration: After a steering rack, column, battery, or control unit replacement, the module may power up but fail to participate correctly on the network if setup did not complete.
• Internal power steering control module fault: Internal circuit failure can stop the module from sending its message, but you must verify powers, grounds, and bus integrity before condemning the module.

Diagnosis Steps

You need a professional scan tool with a full network topology view, a wiring diagram, a digital multimeter, and access to service information. A lab scope helps with intermittent CAN faults. For U0131, record freeze frame data such as ignition state, vehicle speed, battery voltage, and all related communication DTCs. Freeze frame shows when the code set. A scan tool snapshot captures live data during an intermittent event.

1. Confirm U0131 with a full vehicle scan. Record whether the code shows as pending, confirmed, current, or history. Note every related U-code, battery voltage code, EPS code, and gateway code. Save freeze frame data, including ignition state, vehicle speed, and system voltage, because those details tell you whether the fault happens at key-on, during driving, or during low-voltage events.
2. Run a network scan before touching the wiring. Check whether the power steering control module appears on the scan tool module list and whether you can enter it. Then inspect the relevant fuses, relays, and power distribution for the steering module. If the module is missing from the network scan, focus first on power, ground, and bus integrity rather than replacing parts.
3. Verify module power and ground with voltage-drop testing under load. Backprobe the power steering control module circuits with the connector connected when possible. Load the circuit and check ground voltage drop while the circuit operates. Ground drop should stay below 0.1 volt. Do not trust unloaded voltage or continuity alone, because a weak ground can show battery voltage with no load and fail under current demand.
4. Inspect the steering module connector, nearby splice points, and harness routing. Look for water intrusion, green corrosion, backed-out pins, terminal spread, rubbed insulation, and damage near the steering rack, column, subframe, or front wheelhouse. Wiggle the harness while monitoring network status on the scan tool. A brief module dropout during movement points to a wiring or terminal fault.
5. If the module has good power and ground but stays offline, test the CAN bus resistance. Turn ignition off and disconnect the battery. Measure resistance between CAN high and CAN low at an accessible connector on that bus. A healthy network reads about 60 ohms. Around 120 ohms or OL points to an open or missing termination. Very low resistance suggests a shorted bus or shorted module.
6. Next, check CAN bias voltage with the ignition on. Measure CAN high to ground and CAN low to ground at the steering module connector or another accessible point on the same network. A healthy biased bus reads around 2.5 volts on both lines. Ignition-off readings do not give a valid reference, because the network bias is only present when the system powers up.
7. Compare the steering module branch of the network to the rest of the bus. If overall bus readings look normal away from the module but collapse at the steering module connector, unplug the steering module and retest. If the network recovers with the module disconnected, suspect the module or its local wiring. If the network still fails, chase the harness or splice between the module and the backbone.
8. Check service information for module wake-up conditions, gateway involvement, and manufacturer-defined network architecture. U-codes are intentionally general under SAE rules, so one vehicle may route the steering module through a gateway while another places it directly on the high-speed bus. Verify the exact module assignment for control module A on that platform before you condemn a controller.
9. If you can communicate with the steering module intermittently, review its data and perform a scan tool snapshot during a road test. Watch for module resets, steering angle data dropouts, assist status changes, and battery voltage dips. Freeze frame tells you what happened when U0131 set. The snapshot captures what happens during the current fault and often exposes an intermittent harness issue.
10. After the repair, clear all codes and repeat the network scan. Confirm the steering module appears consistently, communicates normally, and no related U-codes return. Drive the vehicle under the same conditions shown in freeze frame. A hard communication fault usually returns quickly on key-on. An intermittent or Type B event may need another drive cycle before it confirms.

Professional tip: Do not condemn the power steering control module just because U0131 names it. On many vehicles, another shorted module on the same CAN bus can make the steering module disappear. Always prove power, ground, and bus health first. If unplugging one suspect node restores normal 60-ohm resistance and network communication, you just narrowed the fault without guesswork.

Possible Fixes

• Repair the steering module power or ground circuit: Replace the failed fuse, repair the open feed, or clean and tighten the ground connection after voltage-drop testing confirms high resistance.
• Repair damaged CAN wiring: Fix opens, shorts, or rubbed-through twisted-pair wiring near the steering gear, column, subframe, or splice area when resistance and bias tests show a network fault.
• Clean or replace corroded connectors and terminals: Restore proper terminal tension and remove moisture-related corrosion at the power steering control module or network junctions.
• Correct a low-voltage problem: Repair the battery, charging system, or power distribution issue if freeze frame and live data show the steering module drops offline during low system voltage.
• Repair a network fault in another module or splice pack: Isolate and fix the node that drags the bus down if unplugging that branch restores communication with the steering module.
• Program, configure, or replace the steering module only after circuit proof: If powers, grounds, and bus integrity all pass and the module still will not communicate, follow service information for setup or module replacement.

Can I Still Drive With U0131?

You may still drive with U0131 in some cases, but you should not assume the vehicle remains safe to operate normally. This U0131 code means one or more modules lost communication with the power steering control module A, so steering assist may drop out, become reduced, or return intermittently. On vehicles with electric power steering, that can make the steering wheel much heavier at low speed. Parking, lane changes, and emergency maneuvers become harder. Some vehicles also disable related stability or driver-assist functions when the steering module goes offline. If the steering feels heavy, the power steering warning light stays on, or other network faults appear, stop driving except to move the vehicle for diagnosis. If steering assist still works and no warning messages remain active, the car may be drivable for a short trip to a repair facility, but you still need prompt testing.

How Serious Is This Code?

U0131 ranges from inconvenient to serious, depending on what the steering system does when communication drops out. If the fault only sets as a history code and steering assist works normally, the issue may be an intermittent network or voltage problem. That still needs attention, because it often gets worse. The code becomes a real safety concern when the power steering module stays offline, assist cuts out, or the steering warning light remains on. Heavy steering can catch a driver off guard, especially during parking or sudden avoidance moves. Ignoring the fault can also hide a broader CAN network problem, low system voltage, or water intrusion at a connector. Those issues can spread and create multiple communication DTCs. Treat U0131 as a high-priority repair when it affects steering feel, warning messages, or network reliability.

Common Misdiagnoses

Technicians often misdiagnose U0131 by replacing the power steering rack, steering motor, or control module before they verify power, ground, and network integrity. That wastes money fast. A dead scan link to the steering module does not prove the module failed. Open fuses, weak grounds, connector corrosion, collision damage near the front harness, and low battery voltage commonly produce the same symptom. Another common mistake is checking continuity on a disconnected harness and stopping there. A wire can pass a simple ohms test and still fail under load. Some shops also ignore pending and history network codes in other modules, even though those codes often show whether the failure affects one module or the whole bus. The correct path starts with a full network scan, module presence check, loaded power and ground tests, and then CAN circuit inspection at the steering control module connector.

Most Likely Fix

The most common U0131 repair direction is restoring the steering control module’s power, ground, or CAN communication path rather than replacing major steering parts first. . Harness damage near the subframe or steering gear also shows up often. If those circuits test good and the scan tool still cannot establish communication with the module, then software faults, setup issues, or a failed power steering control module become more likely. After repair, confirm the fix with a complete network scan, road test the vehicle under the conditions that set the fault, and verify that the code does not return. Enable criteria vary by platform, so check service information for the exact confirmation drive cycle.

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.