B1592 – The data line (+) between the head unit and the central display has a malfunction. There is an open circuit. (Mercedes-Benz)

B1592 means the radio or head unit cannot reliably talk to the central display, so the screen may go blank or act erratic. You can still drive the Sprinter, but you may lose infotainment and some on-screen vehicle functions. According to Mercedes-Benz factory diagnostic data, this code indicates an open circuit on the data line (+) between the head unit and the central display. This is a manufacturer-specific body network fault, so the exact wiring path and module names can vary by platform and option content. Treat the code as a direction to test the communication link, not as proof that a display or head unit failed.

B1592 Quick Answer

B1592 on Mercedes-Benz points to an open circuit on the data line (+) between the head unit and the central display. Confirm the harness, connector pins, and terminal fit before replacing any module.

What Does B1592 Mean?

Official definition: “The data line (+) between the head unit and the central display has a malfunction. There is an open circuit.” In plain terms, the vehicle sees a broken communication path on the positive side of the display data link. When that happens, the head unit and central display cannot exchange the messages they need for normal operation.

What the module is checking: the responsible Mercedes-Benz control unit monitors expected data activity and line integrity on the data line (+). It expects valid signaling and plausible responses within a set timing window. Why that matters for diagnosis: an “open circuit” result usually comes from wiring, terminals, or connector issues first. Use the FTB subtype logic too. The -13 suffix aligns with SAE J2012-DA FTB “13 = Open Circuit,” which narrows your testing toward continuity, terminal tension, and signal presence checks.

Theory of Operation

Under normal conditions, the head unit and central display exchange data over a dedicated communication link. That link may run directly between the two units or through an intermediate harness path. The display relies on this data for graphics, menus, and status messages. The head unit relies on the display for user input and confirmation signals.

With B1592 set, the module sees the data line (+) stop carrying usable communication. An open circuit breaks the electrical path, so messages never arrive. The failure can come from a backed-out terminal, corrosion in a connector, or a harness break. It can also appear after accessory work when the dash components get disturbed.

Symptoms

B1592 typically shows up as infotainment display complaints first, then scan-tool communication clues.

• Scan tool behavior Head unit or central display shows “not responding,” missing, or intermittently offline in the control unit list
• Blank screen Central display stays dark, reboots, or freezes on a logo
• No control input Knob, touch, or button commands do not change the screen
• Intermittent operation Display works until a bump or temperature change, then drops out
• Audio oddities Sound works but screen does not, or settings do not save
• Feature loss Backup camera, media menus, or vehicle settings pages disappear or fail to load
• Stored companion codes Other body/infotainment communication or “no message” faults store alongside B1592

Common Causes

• Open circuit in data line (+): A broken conductor stops the head unit and central display from exchanging data on the positive data path.
• Connector not fully seated at head unit or display: Partial engagement backs terminals away from the pins and creates an effective open circuit.
• Terminal spread, push-out, or poor pin fit: Loss of normal terminal tension creates an intermittent open that becomes a hard open with vibration.
• Corrosion or moisture intrusion at connector: Oxidation increases resistance until the module logic interprets the data line (+) as open.
• Harness damage in dash or A-pillar routing: Chafing, pinching, or a previous accessory install can sever the data line (+) between modules.
• Incorrect aftermarket equipment integration: Splice taps, improper adapters, or removed components can interrupt the dedicated data line (+) path.
• Power or ground fault at the head unit or central display: A module that loses power can stop biasing the line, which mimics an open circuit to the other module.
• Internal fault in head unit or central display interface: A failed transceiver stage can prevent the module from driving or sensing the data line (+), even with good wiring.

Diagnosis Steps

You need a scan tool that can perform a Mercedes-Benz network scan, view stored and pending DTCs, and read freeze frame data. Use a DVOM for voltage-drop testing under load and basic line checks. Have back-probe pins, terminal test probes, and a wiring diagram for the head unit-to-display data line (+). A low-amp current clamp helps confirm module wake-up, but it is optional.

1. Confirm B1592 in all modules and run a full network scan. Record whether the head unit and the central display report on the scan. Save freeze frame data. Focus on ignition state, battery voltage, vehicle speed, and any related communication or infotainment DTCs. Freeze frame shows the conditions when the fault set. Use a scan tool snapshot later if the fault turns intermittent during a road test.
2. Perform fast triage before meter work. Check infotainment-related fuses and power distribution feeds. Inspect the visible circuit path in the dash for disturbed trim, recent radio work, or pinched harness sections. A hard open on a continuously monitored circuit often returns immediately at key-on. That behavior helps you separate a hard fault from a one-trip event.
3. Verify power and ground to the head unit and the central display under load. Do voltage-drop testing with the circuit operating. Load the module by commanding it ON with the scan tool or by turning the system ON. Measure ground drop from module ground pin to battery negative. Keep it under 0.1 V while the module operates. Repeat on the power feed side from battery positive to the module power pin. Do not rely on unloaded voltage or continuity alone.
4. Check whether the scan tool can communicate with both the head unit and the central display. If one module stays offline, diagnose that module’s power, ground, and wake-up first. An offline module can cause the other module to log an “open circuit” style line fault. Do not condemn the data line until both modules power up correctly.
5. Visually inspect both connectors for fit and terminal condition. Look for pushed-back pins, spread terminals, bent pins, corrosion, or moisture tracks. Confirm connector locks fully engage. Tug lightly on the harness near the connector while watching for display dropouts. If movement changes behavior, focus on terminal fit and strain relief.
6. Isolate the data line (+) fault with a controlled wiggle test and scan data. Keep ignition ON and the infotainment system powered. Watch for the DTC status to change from stored to current. Monitor any available live data or bus status indicators for the head unit and central display. Trigger a scan tool snapshot during the wiggle test. That snapshot captures the moment the line opens during diagnosis. Freeze frame cannot do that.
7. Test the data line (+) for open circuit end-to-end with modules disconnected. Disconnect the head unit connector and the central display connector. Use the wiring diagram to identify the data line (+) pins. Check continuity from end to end. If the meter shows open, locate the break by splitting the harness at intermediate connectors, if equipped. Do not pierce insulation unless you plan to seal it correctly afterward.
8. Check for high resistance on the data line (+) rather than only an open. Measure resistance end-to-end and compare to a known-good section when possible. A corroded splice can pass a continuity beep yet fail data transmission. If you find elevated resistance, inspect splice packs and inline connectors used in the dash harness.
9. Verify the line does not short to ground or to power while you chase an open. Keep modules disconnected. Check the data line (+) to ground and to battery positive for unintended continuity. A partial short can collapse bias and look like an “open” to module logic. Correct any rub-through or pinch point before you reconnect modules.
10. Recheck line behavior powered with ignition ON after wiring repairs. Communication line bias only exists with the circuit powered, so ignition-off readings do not confirm integrity. With connectors reinstalled, verify both modules appear on the network scan. Clear codes and cycle ignition. Confirm B1592 does not reset immediately.
11. Confirm the fix with an operational test and a re-scan. Operate the infotainment system through normal functions and any customer complaint conditions. Perform a short drive if the freeze frame shows vehicle speed above zero. Recheck for pending and stored codes. A stored code that stays cleared after multiple key cycles confirms the repair direction.

Professional tip: Treat the FTB suffix -13 as your diagnostic compass. SAE J2012-DA defines -13 as “Open Circuit,” which points you toward a broken path, poor terminal fit, or a module that cannot bias the line. Prove the circuit first. You can replace a display or head unit and still have B1592 if the connector tension or harness routing causes the open.

Possible Fixes

• Reseat and lock connectors at the head unit and central display: Restore proper terminal engagement and confirm the fault does not return.
• Repair harness damage on the data line (+): Fix chafed, pinched, or broken wiring using correct splicing methods and strain relief.
• Clean corrosion and correct terminal fit: Remove oxidation, repair water entry sources, and replace damaged terminals that lost tension.
• Restore proper power/ground to the head unit or display: Repair blown fuse causes, poor grounds, or feed issues verified by voltage-drop testing.
• Remove or rework incorrect aftermarket splices or adapters: Return the data line (+) to an uninterrupted, OE-correct path.
• Replace the head unit or central display only after circuit proof: Replace the module only when wiring integrity and power/ground checks pass and the module fails functional tests.

Can I Still Drive With B1592?

You can usually drive a Mercedes-Benz Sprinter 907 with B1592, because this fault targets infotainment communication, not engine control. Expect display-related issues, such as a blank screen, frozen image, missing menus, or no audio control feedback. Do not treat it as harmless, though. If the central display stays dark, you may lose access to vehicle settings and warning message details. That can reduce situational awareness at speed. Also, repeated network dropouts can distract the driver. If the display fails during rain or at night, stop and address the fault soon.

How Serious Is This Code?

B1592 with FTB suffix -13 identifies an open circuit on the data line (+) between the head unit and the central display. In SAE J2012-DA terms, “-13” narrows the fault type to an open. That points away from “software glitch” and toward wiring, connector, or terminal integrity. Most cases stay in the inconvenience category. You lose screen functions and sometimes audio integration. Severity rises if the display carries warning messages or camera views on your configuration. This code does not directly affect braking or steering, but distraction and loss of information can create risk. Confirm the root cause with circuit tests before replacing modules.

Common Misdiagnoses

Technicians often replace the head unit or central display first, because the symptom looks like a failed screen. That wastes money when the real issue is an open on the data line (+) or a backed-out terminal. Another common miss involves checking power and ground only. A module can power up and still lose its data pair. Many shops also ignore the FTB -13 clue and chase shorts. Use that subtype to focus on continuity, terminal drag, and harness movement tests. Finally, people clear codes and declare victory without a road test. The open often returns with vibration or steering column movement.

Most Likely Fix

The most frequent confirmed repair direction for B1592 (-13 open circuit) is restoring continuity on the data line (+) between the head unit and central display. That usually means repairing a damaged wire section, correcting a pin-fit problem, or cleaning and re-terminating a corroded connector. Start at the connectors you can access without disassembly risk. Perform a wiggle test while watching communication status on the scan tool. If the fault toggles, you found a harness or terminal issue. Only consider module replacement after you prove the line stays intact under load and movement.

Repair Costs

Repair cost depends on whether the confirmed root cause is a sensor, wiring, connector issue, or control module problem. Verify the fault electrically before replacing parts.

Last updated: April 3, 2026