Applicable Systems
OBD-II
Symptoms
The check engine light illuminates. Various engine management functions may be affected. An ECM output circuit or actuator has a malfunction.
Possible Causes
- Faulty ECM output driver circuit
- Actuator or relay circuit open or shorted
- Wiring harness damage to ECM output circuit
- Corroded connector at ECM or actuator
- Aftermarket accessory interfering with ECM circuit
Troubleshooting Steps
- Step 1: Connect an OBD-II scan tool and read all stored DTCs and freeze frame data
All DTCs and freeze frame data are retrieved - Step 2: Inspect the related wiring and connectors for the indicated system
Wiring and connectors are in good condition - Step 3: Use a digital multimeter to check sensor voltage, resistance, and continuity per manufacturer specifications
Values are within specified range - Step 4: Test the related actuator, sensor, or solenoid for proper operation
Component operates within specification or fails definitively - Step 5: Clear codes and perform a road test or drive cycle to verify repair
Code does not return and system operates normally
How to Reset
To reset code P0628: 1) Repair the underlying fault. 2) Use an OBD-II scan tool to clear the DTC. 3) Perform a drive cycle to verify the monitor completes. 4) If the code returns, further diagnosis is needed. Caution: Do not clear codes without fixing the root cause.
Frequently Asked Questions
- Q: What does OBD-II code P0628 mean?
Code P0628 indicates: Computer Output Circuit - Code 628. This is a SAE J2012 standard diagnostic trouble code related to Computer Output Circuit.
- Q: How serious is code P0628?
Severity: Major. Immediate attention is recommended.
- Q: Can I drive with code P0628?
Not recommended - may cause further damage.
- Q: How do I fix code P0628?
Diagnose the Computer Output Circuit system, check wiring and connectors, test related components, and replace faulty parts as needed.
Source: SAE J2012 Standard - Powertrain Diagnostic Trouble Codes
Category: OBD-II