P0697: Sensor Reference Voltage Circuit Open
The P0697 code indicates an open circuit in the sensor reference voltage circuit, typically a 5-volt reference supplied by the powertrain control module (PCM) to various sensors like throttle position, manifold absolute pressure, or fuel pressure. An open circuit means the voltage path is broken, often due to a damaged wire, corroded connector, or internal PCM failure. This can cause multiple sensors to malfunction, leading to drivability issues.
1. Most Common Causes
- Open or shorted wiring in the 5-volt reference circuit
- Corroded or damaged connector pins
- Faulty sensor drawing excessive current
- Failed PCM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Multiple sensor-related codes (e.g., P0106, P0122)
- Engine stalling, rough idle, or poor acceleration
- Reduced fuel economy
3. 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 or corrosion.
Step 3: Measure voltage at the sensor connector with a multimeter; should be ~5 volts with key on.
Step 4: If voltage is missing, check for continuity between the sensor connector and PCM.
Step 5: Disconnect sensors one by one to see if voltage returns, indicating a shorted sensor.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can cause unpredictable engine behavior, stalling, or loss of power, which may be dangerous.
How much does it cost to fix?▼
Repair costs typically range from $50 to $150 for wiring repairs or sensor replacement, but could be higher if the PCM needs replacement.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.