P1263 - High to Low Side Short in Cylinder #3 Injector Circuit
The P1263 code indicates a short circuit between the high and low sides of the fuel injector circuit for cylinder #3. This typically occurs when the injector's internal winding fails or the wiring harness is damaged, causing a direct short. The ECM detects an abnormal current draw and sets the code. This can lead to misfires, poor fuel economy, and potential catalytic converter damage if ignored.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire on cylinder #3
- Rough idle, hesitation, or loss of power
- Increased fuel consumption
2. Most Common Causes
- Faulty fuel injector on cylinder #3 (internal short)
- Damaged wiring or connector for injector #3 (chafed, melted, or pinched)
- Corrosion or moisture in the injector connector
- ECM failure (rare)
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect injector #3 wiring and connector for damage or corrosion.
Step 3: Measure resistance between injector #3 terminals (should be 11-17 ohms). If shorted (0 ohms), replace injector.
Step 4: Check for continuity between injector #3 circuit and ground or power; repair short if found.
Step 5: Clear codes and test drive; if code returns, replace injector #3.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a shorted injector can cause misfires, damage the catalytic converter, and potentially harm the engine. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts (injector ~$50-$150) and labor (1-2 hours). Prices vary by vehicle and shop.
5. Commonly Affected Makes
This is a manufacturer-specific code. The exact manufacturer is not confirmed in our current database.