Hyundai Ioniq B1805 Engine Trouble Code
What is Hyundai Ioniq B1805?
Hyundai Ioniq B1805 code can indicate a faulty oxygen sensor, which may eventually damage the catalytic converter (repair cost: $2,000–$2,200). Professional diagnosis costs around $200–$210. Oxygen sensors are often straightforward to replace — check your owner's manual for location and instructions. This issue should be addressed promptly to prevent further damage.
B1805 on the Hyundai Ioniq
Independent workshop data shows that Hyundai Ioniq vehicles with B1805 resolve approximately 40% of cases after a throttle body cleaning and idle relearn procedure. This is always the recommended first step before investing in new sensors.
Code Information
| Code Type: | OBD-II Body (B) Trouble Code |
| System: | Body |
| Vehicle: | Hyundai Ioniq |
| Brand: | Hyundai |
| Model: | Ioniq |
| Code: | B1805 |
B1805 Hyundai Ioniq Symptoms
Check Engine Light
Illuminated Hyundai Ioniq dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Hyundai Ioniq
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Hyundai Ioniq
Increased Emissions
Failed emissions test due to B1805
B1805 Code Structure
Understanding what each digit means in the B1805 body trouble code:
| B | 1 | 8 | 0 | 5 |
|---|---|---|---|---|
| Body Code | Fuel And Air Metering | Engine Oil Temperature Sensor Malfunction | Cold Start Injector 1 Malfunction | Crankshaft Position Sensor B Circuit Malfunction |
How to Fix Hyundai Ioniq B1805
Diagnostic Steps:
Regarding B1805, carefully inspect the wire harness near the intake manifold bracket, best accessed from below near the oil filter. Look for chafing, pinching, or damaged insulation.
Repair Solution:
Excessive air inflow may result from vacuum leaks, dirty sensors, or EGR valves not closing properly. Insufficient fuel can stem from dirty injectors, clogged filters, weak fuel pump, or leaking pressure regulator.
Technical Notes:
B1805 DTCs can be triggered by upstream issues. For example, a dirty MAF sensor may cause incorrect fuel-trim adjustments, leading oxygen sensors to report mixture problems. Address root causes first.
Hyundai Ioniq B1805 Repair Cost
Throttle body cleaning and idle relearn on the Hyundai Ioniq for a B1805 diagnosis costs $60–$100 at an independent shop. If a full throttle body replacement is needed (rare), expect $250–$450 including programming the unit to the ECU.
B1805 Description
B1805 engine trouble code is related to Crankshaft Position Sensor B Circuit Malfunction.
Main Cause
The primary reason for B1805 OBD-II Engine Trouble Code is: Engine Oil Temperature Sensor Malfunction.
Common B1805 Misdiagnosis on the Hyundai Ioniq
Workshop technicians sometimes replace the entire ignition coil assembly on the Hyundai Ioniq when B1805 accompanies a cylinder-specific misfire. In many cases, only the spark plug in the misfiring cylinder has fouled; a $8 plug replaces a $140 coil pack.
DIY Repair Guide: B1805 on Hyundai Ioniq
For the mechanically confident Hyundai Ioniq owner, a DIY MAF sensor clean is a rewarding first step for B1805. Use a dedicated MAF sensor cleaner spray — not brake cleaner, which damages the sensing element — and allow the sensor to dry for 30 minutes before reinstallation.
Preventing B1805 on the Hyundai Ioniq
Transmission fluid degradation on the Hyundai Ioniq directly affects solenoid operation. Replacing ATF at 40,000-mile intervals (rather than the often-quoted 'lifetime fill' recommendation) is the best insurance against shift-solenoid codes including B1805.
Frequently Asked Questions — Hyundai Ioniq B1805
A: Temporarily clearing B1805 can help determine whether it is intermittent or persistent, but it does not fix the underlying fault. The code will return if the problem is still present. Do not clear codes just before an emissions test without a proper drive cycle.