Chevrolet Sonic B1805 Engine Trouble Code
What is Chevrolet Sonic B1805?
Chevrolet Sonic B1805 indicates potential catalytic converter failure. If completely failed, your vehicle may not run properly and fuel economy will suffer significantly. Average replacement cost is $2,000–$2,140. This repair requires professional service and should not be delayed.
B1805 on the Chevrolet Sonic
In cold climates, Chevrolet Sonic vehicles frequently log B1805 during the first winter of ownership. Condensation inside the throttle body creates a temporary short circuit in the position sensor wiring, which clears once the engine warms up — but the fault code remains stored.
Code Information
| Code Type: | OBD-II Body (B) Trouble Code |
| System: | Body |
| Vehicle: | Chevrolet Sonic |
| Brand: | Chevrolet |
| Model: | Sonic |
| Code: | B1805 |
B1805 Chevrolet Sonic Symptoms
Check Engine Light
Illuminated Chevrolet Sonic dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Chevrolet Sonic
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Chevrolet Sonic
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 Chevrolet Sonic B1805
Diagnostic Steps:
The catalytic converter has oxygen sensors before and after it. When warm and in closed-loop mode, the upstream O2 sensor reading should fluctuate, while downstream should remain steady.
Repair Solution:
Verify all electrical connections are clean and tight. Check for damaged wiring, especially in high-heat or high-vibration areas. Use manufacturer wiring diagrams for accurate diagnosis.
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.
Chevrolet Sonic B1805 Repair Cost
ECU software update for the Chevrolet Sonic to resolve the B1805 calibration bug is performed free of charge at a franchised Chevrolet dealer under the technical service bulletin programme. Always confirm the ECU part number and current flash version before spending money on sensors.
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 Chevrolet Sonic
The Chevrolet Sonic is frequently taken to workshops for a B1805 fault where the technician replaces the throttle position sensor (TPS). In a significant proportion of cases, the root cause is a loose or cracked vacuum hose downstream of the throttle body that should have been found in a basic visual inspection.
DIY Repair Guide: B1805 on Chevrolet Sonic
When replacing sensors on the Chevrolet Sonic, always use anti-seize compound on the thread and dielectric grease on the electrical connector. This simple habit prevents the most common causes of sensor-related callbacks after repair.
Preventing B1805 on the Chevrolet Sonic
Ensure the Chevrolet Sonic oil cap and dipstick tube seal are airtight. Even a small crank-case vacuum leak can cause the PCM to log B1805 and, over time, allows moisture-laden air to degrade the engine oil faster than the scheduled service interval.
Frequently Asked Questions — Chevrolet Sonic B1805
A: Contaminated or low-octane fuel can temporarily trigger B1805 through knock retard and lean/rich excursion events. If the code appeared shortly after a fill-up at an unfamiliar station, running the tank close to empty and refuelling with premium is a sensible first step.