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P0136AudiAudi A4 HubAll Audi P0136Low Severity

P0136 on Audi A4

O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)

Factory diagnostic protocol and troubleshooting wire for fault code P0136 specifically for the Audi A4 (2020–2026, 2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP)).

Verified OEM Telemetry & Field Repair Tree
Audi A42020–2026
Audi A4
Sedan2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
A4 SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Drivable (Short Trip)
Low urgency level
Est. Repair Cost
$100 - $300 (DIY: $35 - $100)
Parts & Labor DIY
Check P0136 On Another Audi Model:
Diagnose P0136 on Specific A4 Model Year:

1. Symptoms of P0136 on Audi A4

When the Engine Control Module (ECM/PCM) on your Audi A4 (2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP)) logs fault code P0136, drivers commonly observe:

Illuminated Check Engine Light on Audi A4 (2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP))
Failed state emissions test on Audi A4 (2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP))
No noticeable drivability degradation on Audi A4 (2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP))
Audi A4 OBD-II Port Location
The 16-pin diagnostic connector is located Under driver side dashboard near hood release lever (pink/purple port). Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Audi A4

Historical warranty claims and technical repair bulletins for Audi A4 point to the following failure distribution:

55%
Failing downstream O2 sensor element (Audi OEM Part)
25%
Corroded or road-damaged downstream sensor wiring underneath vehicle (Audi OEM Part)
12%
Exhaust leak near downstream sensor bung (Audi OEM Part)
8%
Faulty heater circuit inside the sensor (Audi OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Audi A4.

3. Step-by-Step DIY Repair Guide for Audi A4

01
Inspect Downstream Sensor Wiring Under Car

Safely raise vehicle and inspect the wiring harness for Bank 1 Sensor 2 for road debris tears, contact with driveshaft, or heat damage. on the Audi A4 equipped with 2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP).

Required Tool: Jack, Jack Stands, Flashlight
02
Test Sensor Heater Resistance

Unplug connector and measure resistance between the two heater wires (usually same color, e.g., black-black or white-white). Normal is 5–16 ohms. on the Audi A4 equipped with 2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP).

Required Tool: Digital Multimeter
03
Replace Downstream Oxygen Sensor

Apply penetrating oil, unthread sensor with 22mm O2 socket, screw in new OEM sensor, reconnect weather-pack plug. on the Audi A4 equipped with 2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP).

Required Tool: 22mm O2 Sensor Socket, Breaker Bar
04
Clear Trouble Codes & Complete Drive Cycle

Clear DTC memory and complete an OBD-II drive cycle to set catalyst and O2 monitors to 'Ready'. on the Audi A4 equipped with 2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP).

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Audi A4 (P0136)

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Direct-fit replacement assembly engineered to OEM tolerances for Audi A4.

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Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

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Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

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BlueDriver Bluetooth Pro OBDII Scan Tool

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Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

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Other Common Fault Codes on Audi A4

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Audi A4:

4. Audi A4 P0136 FAQs

What causes code P0136 to trigger on a Audi A4?

On the Audi A4 (2.0L TFSI Turbo 4-Cyl (EA888 Gen 4 201HP–261HP)), P0136 is most frequently caused by Failing downstream O2 sensor element or Corroded or road-damaged downstream sensor wiring underneath vehicle.

Where is the OBD-II port located on my Audi A4?

On the Audi A4, the 16-pin DLC diagnostic connector is located Under driver side dashboard near hood release lever (pink/purple port). Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Audi A4 with code P0136?

Yes. Sensor 2 is downstream of the catalytic converter and monitors catalyst efficiency rather than air-fuel mixture. Given that P0136 carries a Low severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.