A 2013 Toyota Tundra with 120,000 kilometers is experiencing intermittent stalling and rough idle issues. The engine starts normally but begins to stumble and stall after 30 seconds to 2 minutes. Accelerating often worsens the problem, causing the RPMs to drop and the engine to cough. While a basic code reader displays P1603 (Engine Stall History) and P1605 (Knock Control CPU), the check engine light remains off.
Several troubleshooting steps have already been taken. These include checking for vacuum leaks, verifying the fuel pressure regulator, and replacing the fuel pump assembly. Additionally, the MAF sensor was inspected, the throttle body cleaned, and a new air filter installed. Fuel pressure seems adequate based on a visual inspection after the engine is shut off. Despite these efforts, the problem persists.
The P1605 code points towards a potential issue with the knock control CPU. This system is responsible for detecting and preventing engine knock, which can cause damage. A malfunctioning knock control system could lead to erratic engine behavior and stalling. However, the lack of a check engine light and the presence of the P1603 code suggest a broader issue that might not be directly related to the knock sensor itself.
Possible causes for these issues could include a faulty crankshaft position sensor or camshaft position sensor. These sensors provide critical timing information to the engine control unit (ECU). If they are malfunctioning, the ECU may not be able to properly control fuel delivery and ignition timing, leading to stalling and rough idle. Other potential culprits include wiring harnesses, connectors, or even a problem within the ECU itself.
Further diagnostics are necessary to pinpoint the root cause. Using a more advanced scan tool capable of reading Toyota-specific codes and live data would provide more detailed information about the engine’s performance. This data can help identify specific sensor readings that are out of range or other anomalies that might be contributing to the problem.
Consulting a Toyota specialist or experienced mechanic familiar with these specific codes and this generation Tundra is recommended. They can utilize professional diagnostic equipment and leverage their expertise to accurately diagnose and resolve the issue. Addressing this problem promptly is crucial to prevent potential engine damage and ensure safe and reliable vehicle operation.
