What This Actually Means
In plain language — no jargon
Water has contaminated your fuel tank, like adding water to a gas can. The engine struggles to burn wet fuel properly, causing performance issues.
Symptoms You May Notice
3 known symptoms for this code
Rough idle or hesitation during acceleration
White smoke from exhaust
Engine misfires or stalling
How Your ECU Detects This
Technical sensor logic and voltage thresholds
The ECU monitors fuel injector performance and combustion efficiency through oxygen sensors and misfire detection. Water in fuel changes burn characteristics and creates incomplete combustion, triggering this fault when the ECM detects abnormal fuel system behavior.
Voltage & Parameter Thresholds
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Fuel combustion efficiency | 95-100% complete burn | <90% complete burn detected |
| Misfire count threshold | 0-2 misfires per 1000 cycles | >5 misfires per 1000 cycles |
Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Fuel system cleaner additive
Pour fuel system cleaner into your tank to help dissolve water and improve combustion.
2
Fuel filter
Replace the fuel filter to remove water and sediment trapped in the filter element.
3
Fuel tank drain/flush service
Drain and flush the entire fuel tank at a shop if water contamination is severe.
When to See a Professional Mechanic
Not all fault codes are safe to DIY
Code P1150 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.
How to Clear Code P1150
What happens after you fix the fault
Once the fault is repaired, P1150 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.
✅ Safe to Clear When
- Fault has been diagnosed and repaired
- You want to confirm the repair worked
- Code appeared after a sensor was cleaned
⚠️ Do Not Clear When
- Preparing for an emissions/PUC test
- Root cause is still undiagnosed
- Check engine light is flashing
Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.