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 Volvo S40FACTORY OEM SERVICE PROCEDURE
Central Electronic Module (CEM) DTCS
CENTRAL ELECTRONIC MODULE (CEM) - DTC INDEX
| DTC | Description |
| CEM-0001 | Control Module. Internal Fault. Intermittent Fault |
| CEM-0001 | Control Module. Internal Fault. Permanent Fault |
| CEM-0002 | High Beam Flash. Signal Too Low. Intermittent Fault |
| CEM-0002 | High Beam Flash. Signal Too Low. Permanent Fault |
| CEM-0003 | Lighting Switch. Signal Too Low. Intermittent Fault |
| CEM-0003 | Lighting Switch. Signal Too Low. Permanent Fault |
| CEM-0008 | 15/1-Power Supply. Signal Too Low. Intermittent Fault |
| CEM-0008 | 15/1-Power Supply. Signal Too Low. Permanent Fault |
| CEM-0009 | 15/2-Power Supply. Signal Too Low. Intermittent Fault |
| CEM-0009 | 15/2-Power Supply. Signal Too Low. Permanent Fault |
| CEM-000A | 75-Power Supply. Signal Too Low. Intermittent Fault |
| CEM-000A | 75-Power Supply. Signal Too Low. Permanent Fault |
| CEM-000B | Switch, Front Fog Lamps. Signal Too High. Intermittent Fault |
| CEM-000B | Switch, Front Fog Lamps. Signal Too High. Permanent Fault |
| CEM-000C | Switch, Rear Fog Lamps. Signal Too High. Intermittent Fault |
| CEM-000C | Switch, Rear Fog Lamps. Signal Too High. Permanent Fault |
| CEM-000D | Rheostat, Input. Signal Too High. Intermittent Fault |
| CEM-000D | Rheostat, Input. Signal Too High. Permanent Fault |
| CEM-000E | Speed Signal. Faulty Signal. Intermittent Fault |
| CEM-000E | Speed Signal. Faulty Signal. Permanent Fault |
| CEM-000F | High Beam. Signal Too High. Intermittent Fault |
| CEM-000F | High Beam. Signal Too High. Permanent Fault |
| CEM-0010 | High Beam. Signal Too Low. Intermittent Fault |
| CEM-0010 | High Beam. Signal Too Low. Intermittent Fault |
| CEM-0010 | High Beam. Signal Too Low. Permanent Fault |
| CEM-0010 | High Beam. Signal Too Low. Permanent Fault |
| CEM-001E | Rheostat, Output. Signal Too Low. Intermittent Fault |
| CEM-001E | Rheostat, Output. Signal Too Low. Permanent Fault |
| CEM-0021 | Control Module, Internal Fault. Signal Too High. Intermittent Fault |
| CEM-0021 | Control Module, Internal Fault. Signal Too High. Permanent Fault |
| CEM-0022 | Windshield Wiper, Parking Position Switch. Signal Too High. Intermittent Fault |
| CEM-0022 | Windshield Wiper, Parking Position Switch. Signal Too High. Permanent Fault |
| CEM-0023 | Windshield Wiper, Parking Position Switch. Signal Too Low. Intermittent Fault |
| CEM-0023 | Windshield Wiper, Parking Position Switch. Signal Too Low. Permanent Fault |
| CEM-0024 | Control Module, Internal Fault. Signal Too Low. Intermittent Fault |
| CEM-0024 | Control Module, Internal Fault. Signal Too Low. Permanent Fault |
| CEM-0025 | Bulb Failure Warning Sensor. Signal Too High. Intermittent Fault |
| CEM-0025 | Bulb Failure Warning Sensor. Signal Too High. Permanent Fault |
| CEM-0026 | Bulb Failure Warning Sensor. Signal Too Low. Intermittent Fault |
| CEM-0026 | Bulb Failure Warning Sensor. Signal Too Low. Permanent Fault |
| CEM-0027 | Battery Voltage. Signal Too Low. Intermittent Fault |
| CEM-0027 | Battery Voltage. Signal Too Low. Permanent Fault |
Factory Service Tools
Use the Manual With the Right Hardware
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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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