Severity High
P2266

Water in Fuel Sensor Circuit Low

📅 Last reviewed: July 2026
What does the P2266 code mean?

The P2266 code indicates that the water-in-fuel sensor circuit is reading a voltage lower than expected. This sensor is typically located in the fuel filter or water separator and detects the presence of water in diesel fuel. A low circuit voltage can be caused by a faulty sensor, wiring issues, or a short to ground. If water is actually present, it can damage the fuel injection system.

High
Severity
$50-$150
Typical Cost
High
Frequency

1. Most Common Causes

2. Symptoms You Will Notice

3. Step-by-Step Diagnosis

1

Step 1: Scan for codes and record freeze frame data.

2

Step 2: Visually inspect the water-in-fuel sensor and wiring for damage or corrosion.

3

Step 3: Test sensor resistance and compare to manufacturer specifications.

4

Step 4: Check for water in the fuel filter by draining the separator.

5

Step 5: Repair or replace faulty sensor or wiring as needed.

4. Frequently Asked Questions

Is it safe to drive with this code?

It is not recommended to drive with this code, as water in the fuel can cause severe damage to the injection system. Have the vehicle inspected immediately.

How much does it cost to fix?

The cost typically ranges from $50 to $150 for sensor replacement, but may be higher if water contamination requires fuel system cleaning.

5. Commonly Affected Makes

This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.

6. Related Codes

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