B1748 – Front passenger pressure side impact sensor communication error (Hyundai)

B1748 means the Kona’s airbag system lost communication with the front passenger pressure side impact sensor. In plain terms, the SRS may not react correctly in a side crash. You may also see an airbag warning light, and the system can disable part of side-impact protection as a safety default. According to Hyundai factory diagnostic data, this code indicates a “Front passenger pressure side impact sensor communication error.” This is a Hyundai-defined, manufacturer-specific code. Its exact network path and sensor layout can vary by platform, so you must confirm the sensor location and wiring route with service information for the 2019 Kona.

B1748 Quick Answer

B1748 on Hyundai points to a communication loss with the front passenger pressure side impact sensor. Diagnose power, ground, connector condition, and network integrity before you consider sensor replacement.

What Does B1748 Mean?

Official definition: “Front passenger pressure side impact sensor communication error.” What the module detected: the SRS control unit could not reliably exchange expected data with the front passenger pressure side impact sensor. What that means in practice: the SRS may set a fault and limit side-impact airbag readiness until the communication returns and the system passes self-checks.

What the module is actually checking: the SRS controller monitors the presence, timing, and validity of messages or signal activity from that specific sensor input path. It also checks for faults that make communication impossible, such as an open circuit, short-to-power, short-to-ground, high resistance at a connector, or a module that drops off the network. Why that matters for diagnosis: the DTC points to a suspected trouble area, not a failed sensor. You must prove the communication path fails, then isolate whether wiring, power/ground, or the sensor electronics cause it.

Theory of Operation

On Hyundai SRS systems, side-impact protection uses multiple inputs to decide when to deploy side airbags and curtain airbags. The front passenger pressure side impact sensor contributes fast side-impact detection information from the passenger side. The SRS control unit expects that sensor to “check in” during key-on self-test and to remain available during operation.

B1748 sets when the SRS control unit cannot confirm communication with that sensor. A poor terminal fit, water intrusion in the passenger-side harness, or a power or ground problem at the sensor can stop data transfer. Network faults can also interrupt communication if the sensor shares a bus or signal path with other SRS components. When communication breaks, the SRS controller flags the code because it cannot trust side-impact input data.

Symptoms

You will usually notice a safety warning first, then scan tool evidence of a missing or unstable sensor.

• Scan tool behavior: SRS data shows the front passenger pressure side impact sensor missing, not learned, or intermittently dropping out
• Airbag warning: SRS/airbag lamp stays on after start-up self-check
• Stored DTC: B1748 returns quickly after clearing, sometimes immediately at key-on
• Intermittent fault: warning lamp comes and goes with vibration, temperature, or humidity changes
• Related codes: other SRS communication or sensor supply codes may appear in the same scan
• Fail-safe operation: SRS may disable or limit some side-impact deployment logic until the fault clears
• Post-repair clue: fault appears after passenger-side body repair, interior trim work, or connector disturbance

Common Causes

• Loose or partially seated sensor connector: A backed-out terminal or poor pin fit interrupts data messages and the module flags a communication error.
• Corrosion or moisture intrusion at terminals: Oxidation increases resistance and distorts the digital signal until the SRS cannot validate sensor responses.
• Harness damage in the passenger-side body/seat area: Pinched, chafed, or stretched wiring creates intermittent opens or shorts that drop the sensor off the network.
• Short to ground or short to power on the communication circuit: A rubbed-through wire can pull the line low or high and prevent normal message traffic.
• High-resistance power or ground feed to the pressure side impact sensor: The sensor resets or brown-outs during vibration and the controller logs a communication loss.
• Poor ground quality at a shared body ground point: A weak ground raises ground potential under load and corrupts low-voltage digital communication.
• Previous collision repair or interior work affecting routing: Misrouted harnesses or missing clips let wiring rub on sharp edges and fail later.
• Incorrect aftermarket accessory tap or add-on wiring: Added loads or scotch-lock taps near the circuit introduce voltage drop and electrical noise.
• Fault in the front passenger pressure side impact sensor: Internal sensor electronics can stop responding even when power, ground, and wiring test good.

Diagnosis Steps

You need a scan tool that can access Hyundai SRS data and run a full network scan. Use a DVOM for voltage-drop tests under load. A backprobe kit, terminal test tools, and wiring diagrams matter here. Plan for careful trim removal. Follow SRS safety practices and service information before unplugging SRS connectors.

1. Confirm DTC B1748 in the SRS system and record freeze frame data. Focus on ignition state, battery voltage, vehicle speed, and any related SRS or network DTCs that set at the same time. Freeze frame shows the conditions when the fault set. Use a scan tool snapshot during a wiggle test or road test to capture intermittent dropouts live.
2. Run a full network/module scan and note whether the SRS/airbag control module and related body modules report normally. Then check whether the scan tool shows the front passenger pressure side impact sensor as “present” in SRS data, if the tool supports it. Next, check SRS-related fuses and power distribution feeds before you probe any controller connector.
3. Verify battery and charging health because low system voltage triggers communication faults. Load-test the battery if it fails a quick screen. Check for loose battery terminals and poor main grounds. Recheck DTC status after correcting any voltage supply problems.
4. Verify SRS control module power and grounds with voltage-drop testing under load. Keep the circuit operating and measure ground drop from the module ground pin to battery negative. Accept less than 0.1 V drop. Repeat on the module power feed side from battery positive to the module B+ pin while the module powers up.
5. Inspect the suspected circuit path and connector condition at accessible points. Look for interior water tracks, green corrosion, bent pins, and damaged CPA/lock tabs. Pay attention to harness routing near the passenger-side front body area and any place trim or seat movement can stress wiring. Do not force terminals or spread pins.
6. With ignition ON, check communication line bias voltages at the sensor side and at the module side as service information directs. Communication bias only exists with the system powered. Ignition-OFF readings do not represent operating conditions. If the line sits pinned high or low, isolate by disconnecting the sensor (per SRS safety steps) and rechecking the line behavior.
7. Perform circuit integrity tests between the SRS module and the front passenger pressure side impact sensor. Check for opens, shorts to ground, and shorts to power on each relevant wire. Use a loaded test method when possible, not continuity alone. A wire can show continuity and still fail under vibration due to broken strands.
8. Check sensor power and ground at the sensor connector with a voltage-drop approach. Backprobe the power feed and ground return while the circuit loads. Look for dropouts while you gently flex the harness. If the sensor shares a ground point, voltage-drop that ground point to battery negative under load.
9. Use a controlled wiggle test and scan tool snapshot to reproduce the fault. Manipulate the harness near connectors and known pinch points while monitoring sensor status and DTC counters. If the code flips from pending to stored quickly, treat it as a hard fault. If it stays pending and only sets during movement, target harness and terminal fit.
10. If wiring, terminals, power, and grounds all pass, follow Hyundai service information to substitute a known-good sensor only as a final confirmation step. Clear codes and cycle the ignition. Then verify the sensor stays online and B1748 does not return as pending or confirmed.
11. Confirm the repair with a post-repair scan. Clear DTCs, run an SRS self-check, and perform a road test under similar conditions to the freeze frame. Re-scan all modules to ensure no new communication or SRS DTCs appear. Document the final freeze frame and snapshot results for the work order.

Professional tip: Treat B1748 as “loss of message,” not “bad sensor.” On Hyundai SRS faults, the fastest wins come from voltage-drop testing grounds and catching intermittent connector pin fit issues. Use freeze frame to pick the right conditions, then use a snapshot during a wiggle test to catch the exact moment the sensor drops off communication.

Possible Fixes

• Reseat and secure the sensor connector: Correct a loose lock, restore terminal tension, and verify stable communication on a snapshot.
• Clean and repair terminal corrosion: Remove moisture intrusion, replace damaged terminals, and restore proper pin fit where corrosion distorted contact surfaces.
• Repair harness damage: Fix chafed, pinched, or stretched wiring and restore proper routing and clip retention to prevent repeat failures.
• Repair power or ground feed issues: Correct high-resistance splices, ground points, or fuse/relay contacts confirmed by voltage-drop testing under load.
• Remove improper aftermarket wiring influence: Eliminate accessory taps and reroute added wiring that introduces noise or voltage drop in the SRS circuit path.
• Replace the front passenger pressure side impact sensor after verification: Replace the sensor only after the circuit tests prove power, ground, and communication lines remain stable.

Can I Still Drive With B1748?

You can usually drive a 2019 Hyundai Kona with DTC B1748, but you should not ignore the safety risk. This code points to a communication loss involving the front passenger pressure side impact sensor. That sensor supports the Supplemental Restraint System (SRS) decision-making in certain crash types. When the SRS control module cannot communicate with a required sensor, the system may disable part of the airbag strategy and turn the airbag warning lamp on. Drive only as needed, avoid carrying a front passenger when possible, and schedule diagnosis immediately. Do not attempt DIY probing on SRS wiring or connectors.

How Serious Is This Code?

B1748 is serious because it involves SRS communications, not comfort electronics. In some cases it acts like an “inconvenience” because the vehicle drives normally, but the airbag warning lamp stays on. Treat that lamp as a compromised restraint system until proven otherwise. On Hyundai platforms, a communication error can come from wiring, power/ground to the sensor, connector faults, or a network issue that affects multiple SRS nodes. Diagnosis requires SRS-safe procedures, correct scan tool access, and technician training. Do not replace SRS components casually, and do not use a test light on SRS circuits.

Common Misdiagnoses

Technicians often replace the side impact sensor first because the code text names it, but the DTC only identifies a suspected trouble area. The most common miss involves connector and harness faults near the passenger-side structures, where movement and moisture create intermittent opens and high resistance. Another frequent error involves ignoring power and ground checks at the sensor connector, then condemning the SRS control module. Shops also misread the problem as a CAN-wide failure without checking for other network DTCs. Avoid wasted parts by confirming scan-tool communication behavior, checking for related SRS codes, and verifying circuit integrity under load before any replacement.

Most Likely Fix

The most frequently confirmed repair direction for B1748 on Hyundai vehicles involves restoring reliable connectivity to the front passenger pressure side impact sensor. That usually means correcting a poor connection, terminal tension problem, corrosion, water intrusion, or harness damage in the passenger-side sensor circuit or its network path. A second common direction involves addressing a broader SRS communication issue when multiple SRS-related modules show loss-of-communication symptoms. Do not treat sensor replacement as the default. Verify power, ground, and communication lines at the connector and confirm the scan tool sees the sensor/module consistently before installing parts.

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: March 31, 2026