P1272: Cylinder #2 Injector Circuit Open (High to Low Side)
The P1272 code indicates an open circuit between the high and low sides of the fuel injector for cylinder #2. This typically means the injector coil has failed (open circuit), or there is a wiring/connector issue in the injector circuit. The ECM monitors the injector driver circuit and detects an abnormal voltage drop or lack of current flow, triggering this code. This can cause a misfire, rough idle, and reduced engine performance.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire on cylinder #2
- Rough idle or hesitation during acceleration
- Decreased fuel economy and power
2. Most Common Causes
- Faulty fuel injector on cylinder #7 with internal coil short circuit
- Damaged injector wiring harness with melted or chafed wires making contact
- Corroded or bent pins in the #7 injector connector causing terminal bridging
- Water or fluid intrusion in the #7 injector connector
- Internal injector driver failure within the PCM (less common)
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect injector #2 connector and wiring for damage or corrosion.
Step 3: Measure resistance across injector #2 terminals (should be 11-16 ohms). If open, replace injector.
Step 4: Check for 12V at injector #2 with key on, engine off. If no voltage, check wiring and fuse.
Step 5: Use a noid light to test injector pulse while cranking. If no flash, suspect wiring or ECM issue.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can cause a misfire, reduced engine performance, and potential damage to the catalytic converter due to unburned fuel.
How much does it cost to fix?▼
The cost to fix P1272 typically ranges from $50 to $150 for a DIY injector replacement, or $150 to $400 if professionally diagnosed and repaired, including parts and labor.
5. Commonly Affected Makes
This is a manufacturer-specific code. The exact manufacturer is not confirmed in our current database.