B1742 – Front driver pressure side impact sensor (P-SIS) communication error (Hyundai)

B1742 means the Kona’s airbag system cannot reliably talk to the front driver pressure side impact sensor. In plain terms, the SRS may turn the airbag warning light on and disable some side-impact protection until the fault clears. According to Hyundai factory diagnostic data, this code indicates a “Front driver pressure side impact sensor (P-SIS) communication error.” That description matters because it points to a communication problem, not an automatic sensor failure. Your job is to confirm whether the sensor lost power, lost ground, lost its data path, or dropped off the network due to wiring or connector issues.

B1742 Quick Answer

This Hyundai-specific code sets when the SRS/airbag control module cannot communicate with the front driver pressure side impact sensor (P-SIS). Diagnose the sensor’s power, ground, and communication circuit integrity before replacing any parts.

What Does B1742 Mean?

Official meaning (Hyundai-defined): “Front driver pressure side impact sensor (P-SIS) communication error.” In practice, the airbag control module flags that it cannot trust the sensor’s presence or messages. That typically turns the SRS lamp on and may inhibit side-impact or seat-mounted airbag strategies, depending on Hyundai platform logic.

What the module actually checks: The SRS module monitors whether it receives the expected identification and status communication from the front driver P-SIS. It also watches for message timeouts, invalid data, or a non-responsive sensor node. Why that matters: A communication DTC directs you first to circuit integrity and network conditions. It does not prove the P-SIS itself failed. Per SAE J2012 guidance, the DTC names a suspected area, not the root cause.

Theory of Operation

Under normal conditions, the SRS control module powers the pressure side impact sensor and expects routine communication back. The sensor reports its health status and pressure event information. The module uses that information to support side-impact deployment logic and diagnostic monitoring.

B1742 sets when that communication chain breaks. The SRS module stops seeing the sensor’s expected messages, sees messages it cannot validate, or detects a node that drops on and off. Common break points include poor connector pin fit, corrosion, wire damage near the sensor location, or a supply/ground that collapses under load and resets the sensor.

Symptoms

Drivers and technicians usually notice one or more of these symptoms with B1742:

• Scan tool P-SIS may show “not equipped/not responding,” intermittent data, or a module list dropout related to the side impact sensor
• SRS light airbag warning lamp illuminated on the cluster
• Stored DTCs additional SRS communication or sensor-related codes stored with B1742
• Intermittent fault warning light comes and goes with bumps, door slams, or temperature changes
• No crash readiness SRS system may report a reduced readiness or disabled side-impact function
• Freeze frame clues code may log as current during key-on self-check, then change to history
• Post-repair indicator code returns immediately after clearing if the sensor never comes back online

Common Causes

• Sensor power feed interruption: A blown fuse, loose fuse fit, or poor power distribution connection prevents the P-SIS from powering up and joining communication.
• High-resistance ground at the sensor: Corrosion or a loose ground point drops voltage under load and the sensor resets or stops responding on the network.
• Open or short in the P-SIS communication circuit: A broken wire, pinch point, or short-to-ground/short-to-power blocks data traffic between the P-SIS and the airbag control module.
• Connector damage or poor terminal tension: Spread terminals, water intrusion, or partially seated locks create intermittent contact that looks like a communication loss.
• Harness damage near the front structure: Front-end impact, bumper service, or radiator support work can stretch, rub through, or misroute the harness feeding the front driver P-SIS.
• Incorrect part or incompatible calibration: A wrong sensor variant or an uninitialized replacement may not handshake correctly with the Hyundai SRS network.
• Control module network disturbance: Another module pulling the shared communication line low can cause multiple network DTCs and a false “sensor communication” report.
• Low system voltage event: A weak battery, poor charging, or voltage dip during cranking can drop the sensor offline and set a stored code.

Diagnosis Steps

Use a scan tool that can access Hyundai SRS data, run a network scan, and read freeze frame. Have a quality DMM, back-probes, and a way to load circuits for voltage-drop tests. Keep the service information and connector views available. Follow all SRS safety practices and disable the system per Hyundai procedure before disturbing connectors.

1. Confirm B1742 and record all DTCs from every module. Save freeze frame for B1742 and note ignition state, vehicle speed, battery voltage, and any related SRS or network codes. 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/module scan and verify whether the scan tool can “see” the SRS module and any SRS sub-components that report on the data list. For communication faults, confirm whether other communication DTCs appear. Multiple communication codes push you toward a shared power or network issue. If B1742 stands alone, focus on the P-SIS circuit path and its local power/ground.
3. Check fuses and power distribution feeding the SRS system and any sensor supply circuits before you meter the module. Verify fuse integrity with a loaded test, not just visual inspection. Confirm the fuse receives power on the correct key position. Also check for loose fuse fit or heat damage at the fuse box terminals.
4. Verify SRS module power and grounds with voltage-drop testing under load. Command a scan tool function that keeps the module awake if available, or test during key-on. Measure ground drop from module ground to battery negative with the circuit operating. Keep acceptable ground drop under 0.1 V. A high-resistance ground can pass continuity checks and still fail under load.
5. Disable the SRS system using Hyundai procedures and wait the specified time before disconnecting connectors. Then inspect the front driver pressure side impact sensor connector and nearby harness routing. Look for water tracks, bent pins, terminal push-out, broken locks, and any evidence of prior bumper or front-end repair.
6. Inspect the harness along its full path between the P-SIS and the SRS wiring junctions. Focus on rub points at brackets, sharp edges, and areas near the radiator support and front structure. Repair obvious damage first. Do not replace the sensor until the circuit integrity checks pass.
7. Reconnect the system as required for live checks, then verify the P-SIS power and ground at the sensor connector using the correct key state. Use ignition ON for communication checks because the network bias voltage only exists when powered. Perform a loaded ground test at the sensor ground and confirm the voltage drop stays below 0.1 V while the circuit operates.
8. Check the P-SIS communication circuit for opens and shorts with the system powered down per SRS safety steps. Verify end-to-end continuity on each communication conductor and check for short-to-ground and short-to-power. Do not rely on resistance alone for intermittent faults. Follow up with a wiggle test while watching the meter for dropouts.
9. With ignition ON, verify communication line behavior at the sensor connector using the DMM and scan tool correlation. Do not use ignition-off readings as a reference. If the line bias looks abnormal or unstable, isolate the branch by disconnecting other devices on the same leg if the service information shows a shared splice. A shorted branch can pull down the entire circuit and mimic a failed sensor.
10. Use the scan tool data list to look for the P-SIS status or identification fields. If the scan tool shows the sensor as “not installed,” “not recognized,” or “no communication,” repeat your connector and terminal tension checks. If the status flips during a harness wiggle, you have a connection or harness fault. Capture a snapshot during the wiggle test to document the dropout timing.
11. Clear codes and cycle the key. For a hard communication fault monitored continuously, B1742 often returns quickly on key-on. If it returns immediately, recheck power, ground, and the communication circuit for a hard open or short. If it returns only after driving, focus on vibration points and voltage stability.
12. Confirm the repair with a final scan after a road test under similar conditions to the freeze frame. Verify no pending or stored B1742 returns. If Hyundai uses a two-trip logic for stored status on your platform, distinguish pending from confirmed/stored results. A pending return after one drive points to an intermittent condition that still needs correction.

Professional tip: Treat B1742 as a network/circuit integrity problem first, not a sensor failure. Terminal tension problems create the most convincing “communication” faults on Hyundai front-end harnesses. Prove power and ground quality with voltage-drop tests, then prove the communication pair integrity, before you authorize any SRS component replacement.

Possible Fixes

• Restore power supply integrity: Replace the failed fuse or repair the power distribution issue that prevents the P-SIS from powering up.
• Repair ground path: Clean and secure the sensor or shared ground point and repair corroded terminals confirmed by excessive voltage drop.
• Repair wiring or terminals: Fix opens, shorts, rubbed-through wiring, or poor terminal tension in the P-SIS communication circuit and connector.
• Correct harness routing and protection: Re-route and secure the front harness away from chafe points, then add proper loom or retention where needed.
• Initialize/configure per Hyundai service procedure: If the platform requires setup after sensor replacement, perform the required learn-in or coding steps and verify communication returns.
• Replace the P-SIS only after circuit proof: Replace the front driver pressure side impact sensor only when power, ground, and communication circuits test good and the sensor still will not communicate.
• Address network-wide interference: Repair another module or branch circuit that drags down the shared communication line when evidence shows multiple communication DTCs.

Can I Still Drive With B1742?

You can usually drive a 2019 Hyundai Kona with B1742, but you should treat it as a safety-related fault. This code points to a communication loss involving the front driver pressure side impact sensor (P-SIS). Hyundai uses that sensor input as part of the side impact sensing strategy on some platforms. The vehicle will normally run and shift fine. The risk involves the Supplemental Restraint System response in a side impact. Do not ignore an SRS warning lamp. Avoid carrying passengers until a qualified shop diagnoses the fault. Do not probe SRS connectors with test lights or improvised tools.

How Serious Is This Code?

B1742 rates as high severity because it involves SRS communication integrity, not comfort electronics. When the SRS module cannot exchange valid messages with the front driver P-SIS, it may disable part of the side impact protection strategy or log the system as compromised. That outcome varies by Hyundai platform and software logic. Driveability effects stay minimal, but occupant protection can change in a crash. Diagnosis requires SRS-capable scan equipment and technician training. Technicians must follow Hyundai’s depower procedures and connector handling rules. DIY repair does not fit this fault because accidental deployment and improper restoration both create real injury risk.

Common Misdiagnoses

Many misdiagnoses start with replacing the P-SIS sensor immediately. That wastes money because a “communication error” often traces to power, ground, or connector issues. Technicians also blame the CAN network without checking the local sensor harness first. On the Kona, front door and pillar wiring sees frequent flex and moisture exposure. Another common mistake involves clearing codes repeatedly and calling it fixed. Intermittent opens return after the next key cycle or vibration event. Some shops also test with an ohmmeter on SRS circuits. That step can violate Hyundai SRS handling practices and can damage sensitive electronics.

Most Likely Fix

The most commonly confirmed repair direction involves correcting a wiring or connection fault between the SRS controller and the front driver pressure side impact sensor. Start with a careful connector inspection for water intrusion, terminal spread, or partial engagement. Follow with circuit checks that verify sensor power and ground integrity under load, plus continuity and short checks on the communication lines using approved methods. If the wiring proves solid and the scan tool still shows lost communication or no sensor data, then sensor replacement becomes a reasonable next step. After repairs, confirm the SRS lamp stays off through multiple key cycles and a road test. Monitor run criteria vary by Hyundai, so use service information to confirm the SRS self-check completed.

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 2, 2026