KONNWEI KW901 – Bluetooth OBD2 Adapter (ELM327 25K80) for Diagnostics, Data Stream & I/M Readiness

The KONNWEI KW901 is a compact and low-power Bluetooth OBD2 adapter that transforms your iOS/Android mobile or tablet into a powerful fault code reader and real-time monitor. With stable connectivity via Bluetooth 5.0 (backward compatible) and the proven ELM327 25K80 platform, you can read/clear engine fault codes (MIL), check I/M Readiness before inspection, and monitor a range of important sensors in real-time such as RPM, speed, coolant temperature, lambda/O2 sensor data, intake manifold pressure, load, MAF, and much more.

The adapter supports all OBD-II/EOBD protocols including CAN, ISO9141-2, KWP2000, SAE J1850 PWM/VPW and works on OBD2-compatible gasoline and diesel cars (12 V). Thanks to its automatic sleep mode function, the KW901 draws minimal power when the car is off, and its small size allows it to remain plugged in without being in the way.

The KW901 is perfect for those who want to diagnose "Check Engine", analyze live data, create logs/reports, and track consumption/trim values. Want to see more readers and accessories? Visit our collection of fault code readers.

Introduction – What the KW901 Is and Does

The KONNWEI KW901 connects your smartphone/tablet to the car's control unit via the OBD2 port (16-pin). Through a compatible OBD app, you can immediately read engine-related faults (DTC), clear fault codes after action, and visualize live data in list or graph view. The adapter supports I/M Readiness, allowing you to check that monitoring systems are "Ready" before inspection.

The integrated ELM327 25K80 solution provides fast and reliable communication. The KW901 works with older protocols (ISO9141-2/KWP2000/SAE J1850) as well as modern CAN buses. With Bluetooth 5.0 (classic/BLE), you get a stable connection with low power consumption, and automatic sleep-mode that protects the car's battery when the car is turned off.

Specifications

• Model: KONNWEI KW901
• Chipset: ELM327-compatible base with 25K80 controller (high compatibility/stability)
• Connection: Bluetooth 5.0 (supports iOS/Android; backward compatible with 4.x)
• Range: up to approx. 10 m (line of sight)
• Power Supply: 12 V via OBD port (auto sleep mode after inactivity)
• Power Consumption: approx. 0.75 W (with power switch/auto-sleep)
• Operating Temp.: −20 °C to +70 °C (storage −40 °C to +125 °C)
• Dimensions: 70 × 32 × 30.5 mm (≈ 2.75″ × 1.25″ × 1.2″)
• Material: ABS, automotive-grade plastic
• LED/Indication: Status/Communication
• Protocol Support: ISO9141-2, ISO14230-4 (KWP 5-baud/fast), ISO15765-4 (CAN 11/29-bit, 250/500 kbit/s), SAE J1850 (PWM/VPW), SAE J1939, USER1/USER2 (CAN user speeds)
• Compatible Platforms: iOS & Android (supported in popular OBD apps)
• In-App Functions: Read/clear DTC, I/M Readiness, live data (PID), freeze frame, sensor graphs, log/export, warning light reset (MIL)
• Colors: Black / Black-Orange / Black-Red
• Warranty: 12 months

Features & Use Cases

• Diagnose "Check Engine" (MIL): Read both generic (P0) and manufacturer-specific (P1) codes, get descriptions, and clear after remedy.
• I/M Readiness: Quick check of emission monitors (e.g., O2, CAT, EVAP, EGR) before inspection.
• Live data stream: Monitor RPM, speed, coolant temp, MAP/MAF, load, ignition advance, fuel trims, etc., in real-time.
• Freeze frame: Capture sensor data from the moment the fault code was set – ideal for intermittent faults.
• Log & export: Record driving data, save reports for comparison before/after repair.
• Remote monitoring: Allow workshops/customers to share data/reports for faster troubleshooting.
• Use cases: Pre-inspection, troubleshooting idle/jerking, lambda/trim check, thermostat diagnosis, air leak indicator (MAP/MAF), fuel pressure sensor via OBD, and more.

Protocols & Compatibility

The KW901 is designed for OBD2/EOBD-compatible 12V vehicles. General guidelines:

• USA: Cars/light trucks from 1996→.
• EU: Gasoline typically 2001→, Diesel typically 2004→ (EOBD).
• Others: Varies – check "Vehicle Emission Control Information" label and OBD2 port.

Note: 24V heavy vehicles are not supported. Some JOBD (Japanese variants) may have limitations. For advanced brand-specific systems (ABS/SRS/EPB, etc.), a full-system scanner is recommended. Explore more options in our fault code reader collection.

Manual / Installation Guide (iOS & Android)

Preparation

1. Park safely. Turn off the ignition.
2. Locate the OBD2 port (usually under the dashboard on the driver's side).
3. Insert the KW901 into the port. Ensure the connection is fully seated.

Step A – Pairing

Step B – App Configuration (General)

1. Select Adapter Type: ELM327.
2. Select Connection: Bluetooth/BLE.
3. Select Protocol: Auto (the app/adapter usually identifies the correct protocol).
4. Press Connect – wait until the status shows connected and PIDs start flowing in.

Quick Start – Reading & Clearing Fault Codes

1. Open the DTC/Check Engine tab in the app.
2. Press Read/Scan to retrieve fault codes.
3. Note codes & descriptions (e.g., P0420 Cat efficiency).
4. Address the cause. Then clear codes with Clear (ignition on, engine off, if the app requires).

Quick Start – I/M Readiness

1. Open the I/M (Readiness/Monitors) tab.
2. Verify that critical monitors are Ready (green). If Not Ready – perform the recommended drive cycle according to the car model.

Quick Start – Live Data & Logging

1. Select Live Data/Realtime.
2. Select desired PIDs (e.g., RPM, ECT, STFT/LTFT, O2, MAP/MAF, VSS).
3. Switch to graph view to see trends and relationships.
4. Start logging to save a drive (perfect for road tests and intermittent faults).

Safe Removal

1. Close the app's connection (Disconnect).
2. Turn off the ignition and carefully pull out the KW901.

I/M Readiness & Inspection

I/M Readiness indicates whether the car's emission-related self-tests (monitors) have been completed after code clearing or battery replacement. Typical monitors: Misfire, Fuel System, Comprehensive, O2, Catalyst, EVAP, EGR. If any are Not Ready, the car may fail the emissions test. Use the KW901 to check the status and perform the vehicle's recommended drive cycle until everything is Ready.

Data Streams & Sensors – Examples & Interpretation

• ECT – Coolant Temp: 85–95 °C during normal operation; slow warm-up may indicate a faulty thermostat.
• STFT/LTFT – Fuel Trims: Normal ±5–10 %; large positive values → lean mixture (air leak/MAF), negative → rich mixture.
• O2 Sensors/Lambda: Pre-cat should fluctuate; post-cat more stable. P0420/P0430 indicates catalytic converter/exhaust leak/sensor problem.
• MAP/MAF: Indicates airflow; deviating values can point to leaks/dirty MAF.
• Ignition Advance: Expected increase with RPM/load; illogical behavior may indicate a sensor fault.
• EVAP Pressure: Used to locate vapor leaks (small EVAP leaks often cause sporadic fault codes).

Troubleshooting & Frequently Asked Questions (FAQ)

Adapter not found on phone

• Check that the ignition is on and the KW901's LED is blinking.
• On iOS: go via the app's own connection screen (BLE), not the iOS Bluetooth list.
• Airplane mode off, Bluetooth enabled. Try restarting the app/phone.

App connects but no data displayed

• Select Protocol = Auto or the correct specific protocol in the app's settings.
• Start the engine if the app requires it for live data.
• Check that other apps are not connected simultaneously (one adapter, one app at a time).

Can the KW901 clear all lights?

The KW901 handles engine/MIL via OBD2. ABS/SRS/service and others are brand-specific systems that require a full-system scanner.

Does it work on diesel?

Yes, if the vehicle is OBD2-compatible (in EU typically 2004→). Some older diesels lack full OBD2 support.

Does it drain power if left plugged in constantly?

The KW901 has auto-sleep. Power consumption in standby is very low, but we recommend removing the adapter during long-term parking.

Which app should I use?

The adapter works with common OBD apps (ELM327-compatible). Choose an app based on your needs (code reading, gauges, logging). No external links are required.

Tips & Best Practices

• Log before/after: Record data before and after repair to confirm the remedy.
• Sensor pairs: Compare pre- and post-cat O2 for catalytic converter diagnosis.
• Vacuum index: MAP/MAF/trim together reveal leaks in the intake system.
• Freeze frame: Analyze freeze frame to understand when the fault occurred (RPM, load, temp).
• Inspection: Check I/M before booking; perform drive cycle if monitors are not ready.
• Supplement your toolbox: See more OBD tools at fault code readers.

Package Contents

• 1 × KONNWEI KW901 Bluetooth OBD2 Adapter
• 1 × User Manual (English)

Important Notices & Disclaimer

• OBD Scope: KW901 covers engine/emissions via OBD2. Brand-specific control systems (ABS/SRS/EPB/Service) require dedicated tools.
• Compatibility: Contact us if you are unsure about OBD2 support. Some work vehicles/Japanese models (JOBD) may have limitations.
• Safety: Always use the KW901 in a safe location. Eyes on the road – prefer logging rather than looking at your phone while driving.
• Battery: Auto-sleep minimizes consumption, but it's advisable to remove the adapter during longer periods of inactivity.
• Emission Laws: Clearing fault codes without addressing the root cause can temporarily hide problems. Always fix the source of the fault.
• No external links: This page only links internally to felkodslasare.se.

Summary

The KONNWEI KW901 is a sleek, affordable, and reliable Bluetooth OBD2 adapter that provides fault code reading, I/M checks, and real-time data in a pocket-sized format. The modern 25K80 platform, automatic protocol selection, and low standby current make it an excellent choice for both DIY mechanics and workshops. Need more options? Check out our collection of fault code readers.