P0697 - Sensor Reference Voltage Circuit Open
The P0697 code indicates an open circuit in the 5-volt reference voltage supply to one or more sensors. This reference voltage is generated by the powertrain control module (PCM) and is used by sensors such as the throttle position sensor, accelerator pedal position sensor, manifold absolute pressure sensor, and others. An open circuit means there is a break in the wiring or a poor connection, preventing the sensor from receiving the proper voltage. This can cause multiple sensors to malfunction, leading to drivability issues.
01. Most Common Causes
- Open or shorted wiring in the 5-volt reference circuit
- Faulty sensor causing a short to ground or power
- Corroded or loose connector pins
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Multiple sensor-related codes (e.g., P0121, P0221, P0106)
- Poor engine performance, hesitation, or stalling
- Transmission shifting issues
03. Step-by-Step Diagnosis
Step 1: Scan for all codes and note which sensors share the 5-volt reference circuit.
Step 2: Visually inspect wiring and connectors for damage, corrosion, or loose connections.
Step 3: With key on engine off, measure voltage at the sensor connector (should be ~5V). If 0V, check for continuity from sensor to PCM.
Step 4: Disconnect sensors one by one while monitoring voltage; if voltage returns, the last disconnected sensor is likely shorted.
Step 5: If all sensors and wiring check out, test PCM output at the PCM connector; if no voltage, PCM may be faulty.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The open circuit can cause erratic sensor readings, leading to poor drivability, stalling, or transmission issues. It may also affect safety systems like traction control.
How much does it cost to fix?▼
The cost typically ranges from $100 to $300, depending on the cause. Simple wiring repairs may be cheaper, while replacing a PCM can cost $500 or more.