Detailed Description of Error P0737
The OBDII error code P0737 is a generic trouble code that indicates a problem with the Transmission Control Module (TCM) engine speed output circuit. The TCM is responsible for controlling the transmission''s gear shifts, torque converter engagement, and other functions. The engine speed output circuit is a critical component of the TCM, as it provides the engine speed signal to the TCM, which is necessary for proper transmission operation.
When the Powertrain Control Module (PCM) detects a malfunction in the TCM engine speed output circuit, it sets the P0737 code and illuminates the Check Engine Light (CEL). This code is often accompanied by other transmission-related codes, such as P0700, P0715, or P0720.
The P0737 code can cause a range of symptoms, including erratic shifting, slipping, or hesitation, as well as a decrease in fuel efficiency and overall engine performance. In severe cases, the transmission may fail to engage into gear or may become stuck in a single gear, leading to a loss of power and control.
Possible Causes of Error P0737
- Faulty Transmission Control Module (TCM)
- Corrosion or damage to the TCM engine speed output circuit wiring
- Faulty engine speed sensor or crankshaft position sensor
- Incorrect engine speed sensor or crankshaft position sensor installation
- Faulty Powertrain Control Module (PCM)
- Corrosion or damage to the PCM engine speed input circuit wiring
- Transmission internal mechanical failure, such as a faulty valve body or solenoid pack
- Low transmission fluid level or dirty transmission fluid
- Aftermarket performance modifications or tuning that affect transmission operation
Possible Fixes for Error P0737
- Use a scan tool to monitor the engine speed signal and transmission operation to identify the root cause of the problem
- Inspect the TCM engine speed output circuit wiring for corrosion or damage and repair or replace as necessary
- Check the engine speed sensor or crankshaft position sensor for proper installation and operation
- Replace the faulty TCM or PCM if necessary
- Check the transmission fluid level and condition, and top off or replace as necessary
- Inspect the transmission for internal mechanical failure and repair or replace as necessary
- Re-flash the PCM with the latest software calibration to ensure proper transmission operation
- Consult with a professional mechanic or transmission specialist if the problem persists