What are the common causes of P0699?

A short to voltage on the C reference circuit. A failed sensor or module on the C circuit. A corroded or open ground. A faulty ECM. A charging system overvoltage.

Monitor the C reference voltage live. Check for a short to power. Test sensors on the C circuit. Check the ECM ground. Repair the circuit or replace the ECM. Clear the code and retest.

P0699

Sensor Reference Voltage C Circuit High

System: Computer output circuits (P code)
Lamp: Check Engine Light
Category: Powertrain - Computer and Auxiliary Controls

What it means

P0699 means Sensor Reference Voltage C Circuit High.

Where it lives

For P0699, the circuit described runs through the sensor. The description of P0699 reports a fault at the sensor.

Check these first

A short to voltage on the C reference circuit
A failed sensor or module on the C circuit
A corroded or open ground
A faulty ECM
A charging system overvoltage

What to do next

Monitor the C reference voltage live
Check for a short to power
Test sensors on the C circuit
Check the ECM ground
Repair the circuit or replace the ECM
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.