Detailed Description of Error P0690
OBDII error code P0690 is a generic trouble code that indicates a problem with the Engine Control Module (ECM) or Powertrain Control Module (PCM) power relay sense circuit. This circuit is responsible for providing power to the ECM/PCM, which is the brain of the vehicle''s engine management system. The power relay is controlled by the ECM/PCM and is used to switch the power supply to the module on and off. When the ECM/PCM detects a high voltage condition on the power relay sense circuit, it sets the P0690 code.
The power relay sense circuit is designed to monitor the voltage supply to the ECM/PCM and ensure that it remains within a specified range. If the voltage exceeds the maximum allowed limit, the ECM/PCM will shut down to prevent damage to the module or other electrical components. The P0690 code is typically accompanied by other trouble codes that indicate a problem with the engine management system, such as P0600, P0602, or P0603.
Possible Causes of Error P0690
- Short circuit in the power relay sense circuit
- High resistance in the power relay sense circuit
- Failed or faulty power relay
- ECM/PCM internal fault or malfunction
- Wiring or connector damage in the power relay sense circuit
- Corrosion or water damage in the power relay sense circuit
- Incorrect or faulty wiring repair
- Aftermarket accessories or modifications that interfere with the power relay sense circuit
Possible Fixes for Error P0690
- Check the power relay sense circuit for signs of damage, corrosion, or wear
- Use a multimeter to measure the voltage in the power relay sense circuit
- Check the power relay for proper operation and replace if necessary
- Inspect the ECM/PCM and its connectors for signs of damage or corrosion
- Check the wiring and connectors in the power relay sense circuit for damage or corrosion
- Use a scan tool to monitor the power relay sense circuit and identify the source of the high voltage condition
- Consult a professional mechanic or the vehicle''s repair manual for further diagnosis and repair