P1273: Cylinder #3 Injector High-to-Low Side Open Circuit
Code P1273 indicates an open circuit between the high and low sides of the fuel injector driver circuit for cylinder #3. This typically means the injector coil has failed (open winding) or there is a wiring/connector issue between the ECM and the injector. The ECM monitors current flow; when it detects no current, it sets this code. This can cause a misfire, rough idle, and reduced power.
01. Most Common Causes
- Faulty fuel injector (open coil) on cylinder #3
- Open or shorted wiring in injector circuit
- Corroded or damaged connector at injector or ECM
- Failed ECM (rare)
02. Symptoms You Will Notice
- Check Engine Light on
- Engine misfire or rough idle
- Reduced power and poor acceleration
- Increased fuel consumption
03. Step-by-Step Diagnosis
Step 1: Scan for codes and note freeze frame data.
Step 2: Visually inspect injector #3 connector and wiring for damage or corrosion.
Step 3: Measure resistance across injector #3 terminals (should be 12-16 ohms). If open (OL), replace injector.
Step 4: Check for 12V at injector harness with key on; if missing, trace wiring back to ECM.
Step 5: Perform a continuity test between injector connector and ECM pin; repair open circuit if found.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a misfire can damage the catalytic converter and cause poor performance. Have it diagnosed promptly.
How much does it cost to fix?▼
Typically $150-$400, including parts (injector ~$50-$150) and labor (1-2 hours). Diagnosis may add $100-$150.