P0697 - SENSOR REFERENCE VOLTAGE C CIRCUIT OPEN

The P0697 OBDII diagnostic code is set because the PCM (Powertrain Control Module) has found an open circuit on a specific sensor, which is designated as C. This sensor is related to the automatic transmission. To determine the location and function of the sensor, you should consult the vehicle’s information source.

The reference voltage is usually 5 volts, and it is applied to the sensor through a switched circuit. This sensor referred to in the code must also be grounded and its resistance is variable.

An input voltage signal is delivered to the PCM because the resistance of the sensor changes with some conditions. If the PCM fails to receive this input signal, the circuit is considered open, and the Check Engine light illuminates next to this code.

• Engine malfunction indicator light ON.
• The transmission fails to shift or has a delay in shifting.
• Correct operation of the transmission is not possible.
• The speedometer does not work properly.

Reasons to set the P0697 OBD2 error code:

• There may be an open circuit.
• There may be blown fuses or their links.
• The power relay associated with the system may be faulty.
• The sensor may be in bad condition.

To troubleshoot the DTC P0697 OBDII code, try this:

• After you determine where the sensor is located and what its function is, check the related fuses. When doing these tests, you should have the circuit at full load. Replace blown fuses. Note that a blown fuse is due to a short in the circuit.
• Inspect cables and connectors that relate to the sensor system. You should fix any faulty components. Then, clear the code.
• Check the reference voltage and ground signal of the sensor with a multimeter. Also, check its resistance and continuity. All results should be compared with the manufacturer's specifications. If they do not meet those specifications, you should replace the sensor.
• If there is no reference voltage at the sensor, the associated controllers should be disconnected. Besides, inspect the circuit resistance and also continuity between the sensor and the PCM. Repair any shorted circuits.