Timing Reference High Resolution Signal B No Pulses
The P0379 code indicates that the Powertrain Control Module (PCM) has detected a loss of the high-resolution timing signal from the 'B' sensor, typically the crankshaft position sensor or camshaft position sensor. This signal is critical for engine timing and fuel injection synchronization. Without it, the PCM may default to a backup mode, causing performance issues.
01. Most Common Causes
- Faulty crankshaft position sensor
- Wiring or connector issues in the sensor circuit
- Damaged reluctor ring or tone wheel
- PCM failure (rare)
02. Symptoms You Will Notice
- Engine may not start or stalls
- Rough idle, misfires, or hesitation
- Check Engine Light illuminated
- Reduced fuel economy and performance
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P0379 and check for related codes.
Step 2: Visually inspect the crankshaft position sensor and wiring for damage or corrosion.
Step 3: Test sensor resistance and AC voltage output while cranking the engine.
Step 4: Check the reluctor ring for damage or debris.
Step 5: If all else fails, test the PCM for proper signal input.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not safe. The vehicle may stall unexpectedly, leading to a loss of power steering and brakes. Have it diagnosed immediately.
How much does it cost to fix?▼
Typically $50-$150 for a sensor replacement, but diagnostic fees and labor can add $100-$200.