P0669 Fault Code

PCM / ECM / TCM Internal Temperature Sensor Circuit High

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0669 code relates to the internal temperature sensor circuit of the Powertrain Control Module (PCM), Engine Control Module (ECM), or Transmission Control Module (TCM). This code indicates that the signal from the internal temperature sensor is reading higher than expected.

• What is the internal temperature sensor? It monitors the temperature of the control module to prevent overheating.
• Why is this important? Proper functioning of the module is crucial for optimal performance of the engine or transmission.
• What can cause this fault? Issues can range from internal sensor malfunction to wiring or connection faults.

What are the symptoms of the P0669 code?

When the P0669 code is triggered, you may observe certain symptoms:

• Check Engine Light (CEL) illuminated on the dashboard.
• Engine or transmission may exhibit erratic behavior.
• Decreased performance or fuel efficiency.
• In some cases, the vehicle may go into limp mode to prevent damage.
• Unusual temperature readings on the dashboard if applicable.

What causes the P0669 code?

There are several potential causes leading to a P0669 code:

• Faulty internal temperature sensor.
• Poor electrical connections or wiring issues resulting in improper readings.
• Short circuits or open circuits within the PCM, ECM, or TCM.
• Overheating conditions due to external factors affecting the control module.
• Corrosion or damage in the connector terminals.

How to fix P0669?

To resolve the P0669 code, several steps should be taken:

• Use an OBD-II scanner to confirm the code and check for any related codes.
• Inspect the wiring and connectors related to the PCM, ECM, or TCM for any visible damage, corrosion, or loose connections.
• Test the internal temperature sensor for proper readings and replace if faulty.
• If the sensor and wiring are intact, the module itself may need servicing or replacement.
• Clear the code and perform a test drive to see if it returns.