Turbocharger Boost Sensor A Circuit Malfunction
The P0235 code indicates a malfunction in the turbocharger boost sensor A circuit. This sensor monitors the boost pressure from the turbocharger and sends a voltage signal to the engine control module (ECM). When the ECM detects an abnormal voltage or signal from the sensor, it sets this code. Common causes include a faulty boost pressure sensor, wiring issues (shorts, opens, or corrosion), or a damaged connector. This can lead to reduced engine performance, poor fuel economy, and potential turbocharger damage if not addressed.
1. Most Common Causes
- Faulty turbocharger boost pressure sensor
- Open or shorted wiring in the sensor circuit
- Corroded or damaged connector at the sensor
- ECM software issues (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or acceleration
- Poor fuel economy
- Possible turbocharger overboost or underboost
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P0235 and check for other codes.
Step 2: Visually inspect the boost sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's voltage and ground supply with a multimeter (reference signal typically 0.5-4.5V).
Step 4: Compare sensor readings with a known good sensor or use a scan tool to monitor boost pressure vs. actual.
Step 5: If wiring and sensor are okay, check for ECM issues or perform a relearn procedure.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause reduced performance and potential turbo damage. Short trips to a repair shop are okay.
How much does it cost to fix?▼
Typically $50-$150 for a new sensor plus labor (1-2 hours). Total cost may range from $100-$300 depending on vehicle and shop rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.