Error Code P0164 – Symptoms, Causes, and Detailed Solutions

What is Code P0164?

Code P0164 is a generic powertrain code that applies to most vehicles built after 1996. It indicates that the Powertrain Control Module (PCM) has detected an abnormally high voltage in the post-catalytic converter oxygen sensor (O2) circuit, specifically for Bank 2, Sensor 3 (B2S3). This crucial sensor monitors oxygen levels in the exhaust gases after they have been treated by the catalytic converter, allowing the PCM to verify the efficiency of the emissions control system.

Symptoms of Code P0164

When this fault appears, several symptoms may alert the driver:

• 🔸 Illumination of the Malfunction Indicator Lamp (MIL)
• 🔸 Decreased engine performance and possible misfires
• 🔸 Noticeable increase in fuel consumption
• 🔸 Possible failure in emissions testing during inspection

Main Causes of Fault P0164

Several factors can be the source of this fault code:

• 🔹 Faulty O2 sensor (Bank 2, Sensor 3)
• 🔹 Wiring problem: damaged wires, short circuits, or corroded connections
• 🔹 Leak in the exhaust system near the sensor
• 🔹 Failure of the oxygen sensor’s heating element
• 🔹 Overly rich air/fuel mixture (if other codes are present)
• 🔹 Problem with the PCM (less common)

Diagnosis and Solutions for Code P0164

🔧 Step 1: Preliminary Visual Inspection

Start with a thorough inspection of the relevant sensor and its wiring. Check for the absence of:

• Physical damage to the sensor or connectors
• Melted wires or contact with hot components
• Signs of corrosion on electrical connections
• Exhaust leaks near the sensor

⚡ Step 2: Electrical Measurements with Diagnostic Tool

Use an OBD2 diagnostic tool to monitor the sensor’s voltage:

• Start the engine and let it reach operating temperature
• Observe the B2S3 sensor voltage – it should normally fluctuate between 0.1V and 0.9V
• If the voltage remains stuck above 0.9V, this confirms the fault

🔍 Step 3: Sensor Circuit Testing

Perform these tests to isolate the source of the problem:

• Test the resistance of the sensor’s heating element (refer to manufacturer specifications)
• Check the continuity and insulation of the sensor wires up to the PCM
• Verify the power and ground for the heating element

🛠 Step 4: Corrective Actions

Based on your diagnostic results:

• Replace the O2 sensor if faulty (use quality OEM parts)
• Repair or replace damaged wiring using appropriate heat sleeves
• Tighten or replace exhaust gaskets if a leak is detected
• Clean electrical connectors with a specialized product

Important Precautions

Before any intervention:

• ⚠️ Always let the engine cool down before handling the exhaust system
• ⚠️ Disconnect the battery before working on the electrical circuit
• ⚠️ Use appropriate tools to avoid damaging the sensor

When to Call a Professional?

If electrical tests seem complex or if you lack the necessary tools, it is recommended to consult a professional mechanic. An accurate diagnosis will prevent unnecessary replacement of expensive parts like the PCM.

Conclusion

Code P0164 typically indicates a problem with the Bank 2 Sensor 3 oxygen sensor or its electrical circuit. A methodical diagnosis often allows for quick identification of the cause and necessary repairs to restore your vehicle’s optimal performance and reduce fuel consumption.

💡 Tip: After any repair, remember to clear the fault codes with your diagnostic tool and perform a relearn procedure if necessary to allow the PCM to adapt to the new sensor’s parameters.