P0699: A high five-volt reference needs a supply-level diagnosis

Ford assigns P0699 to sensor-reference voltage C being too high. The monitored quantity is the reference supply, so the code belongs to a different electrical layer from a single sensor's high-output result.

Use the correct reference criterion

The cited strategy evaluates the reference with ignition on and reports a malfunction after five seconds. Its high boundary is above 5.25 volts. That value is a reference-monitor threshold, not a universal maximum signal voltage for every sensor connected to the controller.

The document also includes a separate reference range/performance strategy for Bosch Tricore modules. Confirm the installed controller and full code before substituting that alternative's limits or detection period.

The channel letter does not locate the fault

“C” identifies the supply group in the diagnostic scheme. The summary does not map that group to particular sensors or harness branches for every vehicle. Use the exact wiring information to establish the connected loads and circuit boundaries.

Ford describes the high condition as a short-to-battery category, but the code does not identify where the unwanted voltage originates. Preserve companion sensor and reference codes before drawing a component conclusion. Verification should demonstrate a stable reference within the appropriate range and valid dependent readings while the monitor runs. A single plausible sensor value does not clear a supply-level fault, and the source does not support automatic PCM replacement.

Source and applicability

This explanation covers the cited Ford monitor variants, not every vehicle displaying this code. Match the engine, sensor architecture and calibration before applying numerical limits.

Ford OBD summary, PDF page 129, Ford OBD summary, PDF page 130.