Sensor Reference Voltage Circuit High
The P0699 code indicates that the Engine Control Module (ECM) has detected a voltage higher than the specified range on the 5-volt reference circuit that powers various sensors (e.g., throttle position, manifold absolute pressure, fuel tank pressure). This can be caused by a short to battery voltage, a faulty sensor, or an internal ECM issue. The high voltage can disrupt sensor readings, leading to drivability problems.
01. Most Common Causes
- Short to voltage in the 5-volt reference circuit
- Faulty sensor (e.g., throttle position sensor, MAP sensor)
- Corroded or damaged wiring/connectors
- Internal ECM failure
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine stalling or rough idle
- Poor acceleration or hesitation
- Other sensor-related codes present
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all codes and freeze frame data.
Step 2: Visually inspect the 5-volt reference circuit wiring and connectors for damage, corrosion, or shorts.
Step 3: Disconnect sensors one by one while monitoring the reference voltage with a multimeter to isolate the short.
Step 4: If voltage remains high with all sensors disconnected, suspect an ECM issue.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended as the high voltage can cause erratic sensor readings, leading to stalling or poor performance. Have it diagnosed promptly.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and repair, but costs can vary if the ECM needs replacement.