Technical Description of OBD-II Trouble Code
The circuit for the Intermediate Shaft Speed Sensor C is experiencing intermittent issues.
What does that mean?
This is a generic diagnostic trouble code (DTC) that typically applies to OBD-II vehicles with automatic transmissions. This can include vehicles from various manufacturers such as Mazda, Toyota, Chrysler, Ford, VW, Dodge, Jeep, Mercedes, Lexus, Chevrolet, etc.
While the code is generic, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
The intermediate shaft, also known as the layshaft, helps distribute rotational force from the input drive to the output shaft inside the transmission. The speed of the intermediate shaft depends on the gear the vehicle is in. In a manual transmission, the gear selector determines the speed, so there is no need to monitor the intermediate shaft speed.
However, in an automatic transmission, the gear is determined by the TCM (Transmission Control Module) using multiple sensor inputs to ensure smooth and efficient shifting. One of these sensors is the Intermediate Shaft Speed Sensor. The TCM relies on this sensor to determine and adjust hydraulic pressures, shift points, and patterns. Experience in diagnosing other types of speed sensors (e.g., VSS, ESS) can be helpful as most speed sensors have similar designs.
The ECM (Engine Control Module) and TCM may activate the P2752 code and associated codes (P2749, P2750, P2751) when they detect a fault in the intermediate shaft speed sensor or its circuits. In some cases, if the sensor fails, the TCM may use other speed sensors within the transmission to maintain functionality by adjusting hydraulic pressure, but this can vary between manufacturers.
The code P2752 indicates an intermittent or erratic signal from the C speed sensor or its circuit. Consult a vehicle-specific repair manual to determine which part of the circuit corresponds to the “C” designation in your particular application.
NOTE: If multiple warning lights are illuminated (e.g., Traction control, ABS, VSC), record any active codes in other systems.
Photo of a transmission speed sensor:
What is the severity of this DTC?
This fault can be moderately severe. While your automatic transmission may still be functioning properly, it could also indicate more significant underlying issues. It is recommended to diagnose any transmission issue as soon as possible.
What are some of the symptoms of the code?
Symptoms of a P2752 trouble code may include:
What are some of the common causes of the code?
Possible causes for this P2752 engine code may include:
What are some P2752 troubleshooting steps?
Basic Step #1
If you are researching this code, it is assumed that you have already checked the transmission fluid level. If not, start by checking the fluid level and ensuring it is clean and at the proper level. Once the fluid is confirmed to be in good condition, locate the intermediate shaft speed sensor. This sensor is often mounted directly to the transmission housing.
You may be able to access the sensor from under the hood, but this may require removing additional components such as the air cleaner, box, brackets, and wires to gain access. Ensure that the sensor and its connector are in good condition and securely connected.
TIP: If the ATF has a burnt smell, it is a sign that new fluid is needed. Consider performing a full transmission service with a new filter, gasket, and fluid.
Basic Step #2
Remove and clean an easily accessible speed sensor. This is a low-cost step, and if the sensor’s pickup is excessively dirty, cleaning it may resolve the issue. Use brake cleaner and a rag to ensure a clean sensor pickup. Dirt or shavings on the pickup can affect the sensor’s readings, so cleanliness is important.
NOTE: Any signs of rubbing on the pickup may indicate inadequate spacing between the reluctor ring and the pickup. If a replacement sensor does not clear the ring, refer to the manufacturer’s procedures for adjusting the pickup/reluctor gap.
Basic Step #3
Test the sensor and its circuit. To test the sensor itself, use a multimeter and refer to the specific manufacturer specifications to measure different electrical values between the sensor’s pins. One useful trick is to perform these tests from the same wires but at the corresponding ECM or TCM connector pins. This will verify the integrity of the harness and the sensor.
