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 the current flow through the injector; when it detects no current (open circuit), it sets this code. This can cause a misfire, rough idle, and increased emissions.
1. Symptoms You Will Notice
- Check Engine Light on
- Engine misfire or rough idle
- Poor acceleration or hesitation
- Increased fuel consumption
2. Most Common Causes
- Faulty fuel injector on cylinder #3 (open coil)
- Open or shorted wiring in injector circuit
- Damaged connector at injector or ECM
- ECM internal failure (rare)
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect injector #3 connector and wiring for damage.
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, check fuse and relay.
Step 5: Perform a continuity test from injector connector to ECM; repair open circuit if found.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the misfire can damage the catalytic converter and cause poor performance. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
Replacing a single fuel injector typically costs $150-$400 including parts and labor. Wiring repairs may be less expensive.
5. Commonly Affected Makes
This is a manufacturer-specific code. The exact manufacturer is not confirmed in our current database.