In order to determine when to execute the next gear change, the vehicle’s computer looks at data from a number of sensors, including the intermediate shaft speed sensor. The ISS sensor measures the rotational speed of the intermediate shaft inside the transmission, so the ECU can know when to up/down shift. If the signal coming from the sensor has intermediate interruptions, a P2748 DTC will be stored.
How Serious is the Code?
Although the symptoms of a P2748 diagnostic trouble code might seem like just a minor annoyance at first, the transmission problems and resulting damage to the internal components, can quickly escalate. You will also experience serious drivability issues that can affect the safety of those in your vehicle.
Symptoms of a P2748 include:
- Harsh, erratic shifts
- Transmission won’t shift gears
- Engine misfire
- Hesitation when accelerating
- Engine stalls when stopped in gear
- Non-working speedometer
- Limp Mode
- Bad intermediate shaft speed sensor
- Faulty transmission input speed sensor
- Malfunctioning transmission output speed sensor
- A wiring short or other damage
- Broken, loose or corroded connectors
- Valve body or pressure related issues
- Solenoid failure
- Failed engine temperature sensor
How to Diagnose the Code?
The first step to diagnosing a P2748 OBD2 trouble code, is to check the level and condition of the transmission fluid. The wiring and connectors on the transmission wiring harness also need to be inspected for signs of damage. The next step would be to research any manufacturer’s TSB’s related to the problem. If everything looks good up to this point, then the intermediate shaft speed sensor will need to be tested directly. The output speed sensor, engine temperature sensor, input speed sensor and shift solenoids may also need to be tested.
What Repairs Will Fix P2748?
- Replace the intermediate shaft speed sensor
- Replace output speed sensor
- Replace input speed sensor
- Repair or replace damaged wiring and/or connectors
- Replace the engine temperature sensor
- Change transmission fluid and filter
- Flush transmission fluid
- Fix transmission fluid leaks
- Reprogram ECU/TCM
- P2745 – Intermediate Shaft Speed Sensor B Circ
- P2746 – Intermediate Shaft Speed Sensor B Circ Range/Performance
- P2747 – Intermediate Shaft Speed Sensor B Circ No Signal
- P2749 – Intermediate Shaft Speed Sensor C Circ
- P2750 – Intermediate Shaft Speed Sensor C Circ Range/Performance
- P2751 – Intermediate Shaft Speed Sensor C Circ No Signal
- P2752 – Intermediate Shaft Speed Sensor C Circ Intermittent