P0848 - Transmission Fluid Pressure Sensor/Switch Circuit High
The P0848 code indicates that the transmission control module (TCM) has detected a voltage signal from the transmission fluid pressure (TFP) sensor or switch that is higher than the expected range. This sensor monitors hydraulic pressure inside the transmission to ensure proper shifting. A high circuit condition typically means there is a short to voltage, a faulty sensor, or an internal transmission issue. This can lead to harsh shifting, slipping, or limp mode.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or delayed shifting
- Transmission slipping
- Transmission stuck in limp mode
2. Most Common Causes
- Faulty transmission fluid pressure sensor/switch 'B' (internal open circuit or short to power)
- Signal circuit wiring shorted to battery voltage (B+)
- Damaged, corroded, or loose terminals at the sensor connector
- Internal TCM/PCM failure (rare)
- Internal hydraulic issues causing erratic readings (less likely for 'Circuit High')
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect wiring and connector for damage, corrosion, or shorts.
Step 3: Test the TFP sensor voltage and resistance per manufacturer specs.
Step 4: Check transmission fluid level and condition.
Step 5: If sensor and wiring are okay, perform a transmission pressure test.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with P0848 can cause transmission damage due to improper pressure regulation. You may experience harsh shifting or slipping, which can worsen internal wear.
How much does it cost to fix?▼
The cost ranges from $50 to $150 for diagnosis and sensor replacement. If internal transmission repairs are needed, costs can exceed $1,000.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.