Quick Answer
P0748 means: P0748 means there's a problem with the transmission fluid pressure sensor circuit, affecting transmission performance.
Can I drive with P0748? Address this issue promptly to avoid serious transmission damage.
Common Questions
What does P0748 mean and how does it affect my car?
The P0748 code indicates a problem with the transmission fluid pressure sensor. This can lead to erratic shifting and reduced power, impacting overall vehicle performance and safety.
What are the most common causes of P0748 and how much does it cost to fix?
Common causes include a faulty pressure sensor, damaged wiring, or low fluid levels. Repair costs typically range from $150 for sensor replacement to $3,500 for a complete transmission overhaul.
Can I drive my car with P0748 or should I stop immediately?
While you might still be able to drive your vehicle, it's advisable to address the P0748 code as soon as possible to avoid severe transmission damage.
How can I diagnose P0748 myself using GeekOBD APP?
You can use GeekOBD APP to scan your vehicle for trouble codes, check the status of the transmission fluid pressure sensor, and view live data to identify performance issues.
What vehicles are most commonly affected by P0748?
The P0748 code is frequently reported in models like the 2005-2018 Honda Accord, Toyota Camry, and Nissan Altima, particularly those with automatic transmissions.
How can I prevent P0748 from happening again?
Regular maintenance, including checking transmission fluid levels and keeping wiring connections clean, can help prevent issues that lead to the P0748 code.
What is P0748?
The P0748 diagnostic trouble code (DTC) indicates a malfunction in the transmission fluid pressure sensor/switch 'A' circuit. This code is prevalent among various vehicles, particularly in models like the 2005-2018 Honda Accord and Toyota Camry. When the engine control module (ECM) detects that the signal from the transmission fluid pressure sensor does not conform to expected parameters, it triggers the P0748 code. This malfunction can lead to serious transmission problems, including slipping, erratic shifting, and, if left unresolved, complete transmission failure. In real-world terms, this may manifest as a vehicle that struggles to change gears smoothly, experiences unexpected power loss during acceleration, or has a check engine light that remains illuminated. The financial implications can be significant, with repair costs ranging from minor fixes like sensor replacements to more extensive and costly repairs involving the transmission. Drivers should take this code seriously, as it not only impacts vehicle performance but can also affect safety on the road.
System: P - Powertrain (Engine, Transmission, Emissions)
Symptoms
Common symptoms when P0748 is present:
- The check engine light is illuminated continuously, signaling the need for diagnostic attention.
- Drivers may notice that the engine hesitates during acceleration, causing a reduction in overall driving performance, especially when merging onto highways.
- Fuel economy may decrease significantly, typically by 10-15%, due to inefficient transmission operation.
- Shifting may become harsh or delayed, leading to a jarring experience when changing gears.
- In some cases, the vehicle may enter 'limp mode', restricting speed and power to protect the transmission from further damage.
Possible Causes
Most common causes of P0748 (ordered by frequency):
- The most common cause of P0748 is a faulty transmission fluid pressure sensor, which occurs in about 50% of cases. This sensor can fail due to wear or exposure to extreme temperatures.
- Another significant cause is damaged wiring or connectors in the transmission range sensor circuit, which can lead to incorrect readings. This issue is often due to corrosion or physical damage, making it crucial to inspect these components.
- A third possible cause includes low transmission fluid levels, which can lead to insufficient hydraulic pressure. Regular fluid checks and changes can prevent this issue.
- Less commonly, a malfunctioning transmission control module (TCM) may trigger the P0748 code. This is a serious issue that requires professional diagnostics.
- Finally, while rare, a complete transmission failure can result in this code. This situation may arise from neglecting earlier symptoms or failing to maintain the vehicle properly.
P0748 Repair Costs
Cost Breakdown by Repair Type
Transmission Fluid Pressure Sensor Replacement
Replacing the faulty transmission fluid pressure sensor can resolve code P0748.
- Total: $150 - $300
- Success rate: 85%
Wiring Repair
Repairing or replacing damaged wiring or connectors in the transmission circuit.
- Total: $100 - $250
- Success rate: 70%
Complete Transmission Service
In cases of severe transmission wear or damage, a complete service may be needed.
- Total: $1,000 - $3,500
- Success rate: 60%
Money-Saving Tips for P0748
- Start with the most common and least expensive repairs first
- Use GeekOBD APP to confirm diagnosis before replacing expensive parts
- Consider preventive maintenance to avoid future occurrences
- Compare prices for OEM vs aftermarket parts based on your needs
- Address the issue promptly to prevent more expensive secondary damage
Diagnostic Steps
Professional P0748 Diagnosis Process
Follow these systematic steps to accurately diagnose P0748. Each step builds on the previous one to ensure accurate diagnosis.
Step 1: Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes)
Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes).
Step 2: Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes)
Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes).
Step 3: Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the transmission fluid pressure sensor (20-30 minutes)
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the transmission fluid pressure sensor (20-30 minutes).
Step 4: Step 4: System function test - Verify proper operation after repairs and clear codes
Step 4: System function test - Verify proper operation after repairs and clear codes. This may include checking for any additional codes that surface (10-15 minutes).
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to confirm the repair was successful (15-20 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm the repair was successful (15-20 minutes).
Important Notes
- Always verify the repair with GeekOBD APP after completing diagnostic steps
- Clear codes and test drive to ensure the problem is resolved
- Address underlying causes to prevent code recurrence
Real Repair Case Studies
Case Study 1: Transmission Fluid Pressure Sensor Fix on 2010 Honda Accord
Vehicle: 2010 Honda Accord, 120,000 miles
Problem: Customer reported check engine light on and harsh shifting.
Diagnosis: Using the GeekOBD APP, we retrieved the P0748 code and found the pressure sensor was faulty.
Solution: Replaced the transmission fluid pressure sensor and performed a transmission fluid change.
Cost: $250 (sensor: $150, fluid: $100)
Result: The check engine light cleared, and shifting returned to normal.
Case Study 2: Wiring Repair on 2015 Toyota Camry
Vehicle: 2015 Toyota Camry, 80,000 miles
Problem: Customer noticed delayed shifts and reduced power.
Diagnosis: Diagnostic revealed damaged wiring in the pressure sensor circuit.
Solution: Repaired the damaged wiring and reconnected the harness.
Cost: $200 (wiring repair: $100, labor: $100)
Result: Restored normal operation with no further issues.