P0737 Fault Code in Volkswagen: Causes, Symptoms, and Fixes

DTC P0737 generally relates to the torque converter clutch (TCC) speed sensor signal—specifically when there’s an incorrect ratio between the input (turbine) speed and output (transmission output shaft) speed. It often occurs when the transmission control module (TCM) detects a mismatch between gear ratios, especially in overdrive gears.

Possible Symptoms:

1. Check Engine Light (CEL) ON
2. Harsh shifting or slipping between gears
3. Poor fuel economy
4. Transmission may go into limp mode
5. Speedometer issues (if output sensor is faulty)

Common Causes:

1. Faulty output speed sensor
2. Faulty input (turbine) speed sensor
3. Wiring issues (damaged, corroded, or loose connectors)
4. Defective transmission control module (TCM)
5. Internal transmission issues (e.g., slipping clutches, faulty solenoids)
6. Incorrect gear ratios caused by damaged gear sets

Related Systems:

1. Transmission control system
2. Speed sensors (input/output)
3. Torque converter clutch (TCC)
4. Valve body or shift solenoids

Possible Fixes:

1. Scan live data to verify input and output speed sensor readings
2. Inspect and test the output and input speed sensors
3. Check for shorts, open circuits, or poor ground connections
4. Replace faulty speed sensor if readings are inconsistent or dead
5. If sensors are good, inspect TCM or internal transmission components
6. Perform a transmission fluid check—dirty or low fluid can cause erratic sensor readings

Applicable Vehicles:

P0737 is more commonly found in Chrysler, Dodge, Jeep, Volkswagen (with Chrysler transmission), and other automatic transmission-equipped vehicles. However, it can appear in a wide range of vehicles with electronically controlled automatics.