P0162 — this is a common OBD-II code.

🔧 Code: P0162

O2 Sensor Circuit Malfunction – Bank 2 Sensor 3

What it means

The ECM/PCM is detecting little or no activity from the downstream oxygen sensor on Bank 2, Sensor 3.

Bank 2 → the side of the engine without cylinder #1

sensor 3 → usually after the catalytic converter (some vehicles only have up to Sensor 2; Sensor 3 is common on V6/V8 with multiple cats)

⚠️ Common Causes

1. Failed O2 sensor (most common)

2. Open or shorted wiring to the sensor

3. Blown heater fuse (if heater circuit shared)

4. Exhaust leak near the sensor

5. Connector corrosion or damage

6. Rare: PCM issue

🧪 Diagnostic Steps (Shop-Friendly)

1 Confirm sensor location

Verify Bank 2 Sensor 3 on the exhaust

Make sure the vehicle actually uses Sensor 3 (some don’t)

2 Visual inspection (very important)

   Check:

Melted wires (close to exhaust)

Broken or stretched wiring

Loose or oil-soaked connector

Exhaust leak upstream of the sensor

🔧 If wiring is damaged → repair first

3 Live data test (scan tool)

Warm engine, monitor:

B2S3 O2 voltage

Normal behavior:

Downstream sensor should be fairly steady

Typically around 0.6–0.8 V

Problem indicators:

Stuck at 0.0–0.1 V

No change at all

Flatline reading

👉 If flatlined → bad sensor or open circuit

4 Heater circuit check (multimeter)

  Key ON, engine OFF:

One wire should have battery voltage

Resistance of heater: typically 5–14 ohms (check spec)

❌ No power or infinite resistance = heater failure

Signal circuit test

Check continuity from sensor to PCM

Check for short to ground or voltage

🔁 Common Fix

✅ Replace Bank 2 Sensor 3 O2 sensor

⚠️ Use OEM or high-quality aftermarket

Cheap sensors cause repeat comebacks

🚗 Driveability Symptoms

Often no noticeable symptoms

Possible failed emissions test

Check Engine Light ON

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