Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2003 Hummer H2FACTORY OEM SERVICE PROCEDURE
Diagnostic Trouble Code Definitions
DIAGNOSTIC TROUBLE CODE DEFINITIONS
| DTC (1) | Description | ||
|---|---|---|---|
| P0562 | Low System Voltage | ||
| P0563 | High System Voltage | ||
| P0615 | Improper Voltage Level On The Output Circuit That Controls The Starter Relay | ||
| P0622 | Out-Of-Range Duty Cycle Signal | ||
| P1637 | Generator Turn-On Signal Circuit Voltage Out-Of-Range | ||
| P1638 | Out-Of-Range Duty Cycle Signal | ||
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Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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