P2528 indicates that the vacuum reservoir pressure sensor circuit is reporting a voltage higher than the expected range. This usually points to an electrical fault in the sensor, its wiring, or the connector, rather than an actual over‑pressure condition in the brake booster vacuum system.
The sensor internally fails and outputs a voltage that exceeds the normal range, triggering the high circuit code.
Damaged insulation, chafed wires, or a short to battery voltage can cause the sensor signal to read excessively high.
Corrosion, moisture, or a poor connection can create erratic voltage readings that the PCM interprets as a high circuit condition.
A rare internal fault in the powertrain control module’s sensor input circuit can falsely register a high voltage; this is considered only after sensor and wiring are verified good.
No. The PCM is rarely the cause of this code; most instances are due to a faulty sensor, wiring, or connector. Replacing the PCM should only be considered after those components have been tested and found good.
A vacuum leak typically leads to low pressure readings, not a high circuit voltage. P2528 is an electrical fault code, so a leak is unlikely to trigger it unless it indirectly damages the sensor or wiring.
Re‑inspect the wiring harness and connector for hidden damage, verify proper grounding, and check for any related codes that might indicate a broader electrical issue. If everything checks out, further PCM diagnostics may be warranted.