Hyundai Elantra B1805 Engine Trouble Code
What is Hyundai Elantra B1805?
Hyundai Elantra 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 Elantra
On the Hyundai Elantra, a triggered B1805 code almost always warrants an immediate inspection of the exhaust gas recirculation (EGR) system. Carbon build-up inside the EGR valve is a well-documented root cause for this platform.
Code Information
| Code Type: | OBD-II Body (B) Trouble Code |
| System: | Body |
| Vehicle: | Hyundai Elantra |
| Brand: | Hyundai |
| Model: | Elantra |
| Code: | B1805 |
B1805 Hyundai Elantra Symptoms
Check Engine Light
Illuminated Hyundai Elantra dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Hyundai Elantra
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Hyundai Elantra
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 Elantra 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:
Firing order is engineered to minimise vibration. Altering firing order results in mistimed ignition and poor engine operation. Consult vehicle-specific repair manual for correct firing order.
Technical Notes:
B1805 on electronically controlled automatic transmissions relates to shift solenoid operation. The solenoid actuates hydraulic circuits controlling clutches or bands for gear changes.
Hyundai Elantra B1805 Repair Cost
MAF sensor replacement on the Hyundai Elantra for a B1805 fault runs $220–$380 at a franchised dealer. OEM-equivalent aftermarket sensors are available for $80–$130 and are a reliable option for vehicles outside the factory warranty period.
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 Elantra
A catalytic converter is often condemned on the Hyundai Elantra when B1805 appears and an efficiency code is present. Before replacement, verify that the upstream oxygen sensor is not slow-responding — a lazy O2 sensor mimics catalytic inefficiency perfectly.
DIY Repair Guide: B1805 on Hyundai Elantra
For the mechanically confident Hyundai Elantra 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 Elantra
Inspecting the Hyundai Elantra wiring harness conduit grommets annually — especially the floor pan grommet — costs nothing and takes 10 minutes. Catching moisture ingress early eliminates the most common electrical trigger for B1805 on this model.
Frequently Asked Questions — Hyundai Elantra B1805
A: B1805 is a standardised OBD-II code that can appear on any make and model. However, the specific components and circuits that trigger this code, and the repair procedures involved, vary significantly between vehicles. The information on this page is focused on the Hyundai Elantra.