The P0739 OBD-II code indicates an issue with the Transmission Control Module (TCM) related to the engine speed output circuit. This code is commonly triggered when the TCM receives an inaccurate signal from the engine speed sensor, which is critical for proper gear shifting in your vehicle.
What Does the P0739 Code Mean?
The P0739 code specifically refers to a fault in the TCM’s engine speed output circuit. This means that the TCM is not receiving the correct information regarding the engine’s RPM, which can lead to improper transmission shifting. In most cases, this issue arises from a failure in the crankshaft position sensor, wiring issues, or a malfunction in the TCM itself.
What Causes the P0739 Code?
Several factors can trigger the P0739 code, including:
- Crankshaft Position Sensor (CKP) failure
- Powertrain Control Module (PCM) failure
- Transmission Control Module (TCM) failure
- Wiring issues related to the engine speed sensor
What Are the Symptoms of the P0739 Code?
Drivers may experience a range of symptoms when the P0739 code is present, including:
- Increased fuel consumption
- Transmission may not shift properly
How Serious Is the P0739 Code?
The severity of the P0739 code is considered moderate. While it may not pose an immediate threat to the vehicle’s safety or functionality, it is crucial to address the issue promptly to avoid more severe problems down the line.
How to Diagnose the P0739 Code
To diagnose the P0739 code, a mechanic will typically:
- Use an OBD-II scanner to confirm the presence of the code and check for additional codes.
- Inspect the engine speed sensor and wiring for any visible damage or loose connections.
- Test the crankshaft position sensor for proper functionality.
- Evaluate the TCM and PCM for any faults.
Common Repairs for the P0739 Code
Common repairs for the P0739 code may include:
- Replacing the crankshaft position sensor
- Repairing or replacing damaged wiring
- Replacing the transmission control module (if found faulty)
- Reprogramming or replacing the powertrain control module (if necessary)
How Much Does It Cost to Fix the P0739 Code?
The cost of repairing the P0739 code can vary significantly based on the underlying issue. Typical costs might range from $100 to $1,000, depending on whether a sensor needs to be replaced, wiring repaired, or modules replaced.
Can I Fix the P0739 Code Myself?
While some vehicle owners may have the skills to diagnose and replace a crankshaft position sensor or repair wiring, it is generally recommended to seek professional help for accurate diagnosis and repairs, especially when it involves the TCM or PCM. Proper tools and expertise are necessary to ensure the issue is resolved correctly.
