P1428 EGI System Functional Test Failure
The P1428 code indicates that the engine control module (ECM) has detected a failure during the routine self-test of the Electronic Gasoline Injection (EGI) system. This system, also known as electronic fuel injection, is responsible for precisely controlling fuel delivery to the injectors. The functional test verifies that all injection system components respond correctly to ECM signals. The failure may result from an incorrect response from the injection actuator, a problem in the injector control circuit, or a communication anomaly between the ECM and injection system components during the programmed test sequence.
01. Most Common Causes
- Faulty EGI system actuator or injection control module
- Open or short circuit in the injection controller wiring
- Corroded or loose connectors in the EGI system harness
- Internal ECM failure preventing proper test execution
- Power supply or ground issue to the EGI module
- Defective fuel injectors or injectors with out-of-spec resistance
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine may run rough, misfire, or have poor fuel economy
03. Step-by-Step Diagnosis
Scan for additional codes and freeze frame data
Visually inspect EGI system wiring and connectors for damage or corrosion
Test fuel injector resistance and compare to specifications
Check power and ground circuits to the EGI module
Perform a functional test of the injection system using a scan tool
If all else fails, test or replace the ECM
1. Frequently Asked Questions
Is it safe to drive?▼
Driving with this code is not recommended as it can cause poor engine performance, increased emissions, and potential damage to the catalytic converter. Have the vehicle diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs vary widely depending on the root cause, typically ranging from $100 for a simple wiring repair to $1,000 or more for ECM replacement.