P0052 – O2 Sensor Heater Control Circuit High (Bank 2 Sensor 1).

✅ P0052 Code Meaning

P0052 = O2 Sensor Heater Control Circuit High (Bank 2 Sensor 1)
This means the heater circuit of the upstream oxygen sensor (Bank 2, Sensor 1) is detecting higher-than-normal voltage.
Usually indicates:

Short to power

Internal heater resistance too low

Wiring issue

Faulty sensor

✅ Bank / Sensor Location

Bank 2 = The side without cylinder 1

Sensor 1 = O2 sensor before catalytic converter (upstream)

🔧 Common Causes

1. Short to battery voltage (+B) in heater circuit

2. Damaged wiring near exhaust manifold

3. Connector melted due to heat

4. Heater element inside O2 sensor shorted

5. Faulty fuse or relay feeding O2 heater circuit

6. ECM/PCM driver issue (rare)

🔍 Step-by-Step Diagnosis

1️⃣ Check Fuse & Power Supply

Locate:

O2 sensor heater fuse

EFI fuse / A/F heater fuse

Check:

Is the fuse blown?

Is the fuse oversized or replaced incorrectly?
(High circuit → sensor may be shorted to power)

2️⃣ Visual Inspection

Look for:

Burnt wires touching exhaust manifold

Melted connectors

Oil or water contamination

Repair any damage.

3️⃣ Check Sensor Heater Resistance

Disconnect Bank 2 Sensor 1 O2 sensor connector.

Using multimeter:

Measure heater element resistance (across heater pins).

Typical resistance:

3 – 20 ohms (most cars)

If:

0–1 ohm → shorted heater → replace sensor

Open circuit → heater failed → replace sensor

4️⃣ Check Wiring to ECM

With ignition ON:

Check one heater wire for battery voltage (12V)

Check the other wire is controlled ground from ECM

If you see constant 12V on both wires → short to power in harness.

5️⃣ Check ECM Driver

If wiring and sensor are OK:

ECM driver may be stuck high
(very rare)

🛠 Most Common Fixes

1. Replace Bank 2 Sensor 1 O2 sensor (most common)
2. Repair shorted heater power wire
3. Replace burnt/melted connector
4. Replace O2 heater fuse
5. Fix harness touching exhaust

Welcome to madurai car service 💐🙏🏻.