Code Definition

P2003 (02) — Controller Power Supply - Feedback Voltage High

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Mercedes-Benz

About P2003

P2003 is a generic (obd-ii standard) powertrain diagnostic trouble code recorded for Mercedes-Benz vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P2003 is stored, the module has detected a signal or supply voltage higher than the expected operating range.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P2003 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

DTC P2003 with sub code 02 is a Mercedes Benz specific code indicating that a control module has detected an abnormally high feedback voltage on its controller power supply circuit. Many Mercedes control modules switch and monitor their own power feeds, and the module checks the feedback voltage on that supply against a calibrated range to confirm the supply is healthy. P2003 sets when the feedback voltage rises above the upper threshold, which typically points to a charging system fault, a wiring problem, or a fault in the power supply or relay feeding the module. When this code is set the af...

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