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P0139 on Toyota Camry TRD

O2 Sensor Circuit Slow Response (Bank 1 Sensor 2)

Factory diagnostic protocol and troubleshooting wire for fault code P0139 specifically for the Toyota Camry TRD (2020–2025, 3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust)).

Verified OEM Telemetry & Field Repair Tree
Toyota Camry TRD2020–2025
Toyota Camry TRD
Sedan3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
Camry TRD 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 P0139 On Another Toyota Model:
Diagnose P0139 on Specific Camry TRD Model Year:

1. Symptoms of P0139 on Toyota Camry TRD

When the Engine Control Module (ECM/PCM) on your Toyota Camry TRD (3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust)) logs fault code P0139, drivers commonly observe:

Check Engine Light on on Toyota Camry TRD (3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust))
Slow switching response on scan tool graphs on Toyota Camry TRD (3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust))
Failed emissions readiness monitors on Toyota Camry TRD (3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust))
Toyota Camry TRD OBD-II Port Location
The 16-pin diagnostic connector is located Driver footwell lower knee bolster panel. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Toyota Camry TRD

Historical warranty claims and technical repair bulletins for Toyota Camry TRD point to the following failure distribution:

55%
Aged and degraded downstream O2 sensor coated in carbon / silicon deposits (Toyota OEM Part)
25%
Exhaust leak near downstream sensor (Toyota OEM Part)
12%
Degraded internal heater in oxygen sensor (Toyota OEM Part)
8%
High electrical resistance in wiring harness (Toyota OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Toyota Camry TRD.

3. Step-by-Step DIY Repair Guide for Toyota Camry TRD

01
Verify Sensor Slow Response on Graph

Use scanner graphing mode. Perform rapid deceleration fuel cutoff. Sensor should drop quickly to 0.1V. If response lags by several seconds, sensor is worn. on the Toyota Camry TRD equipped with 3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust).

Required Tool: Graphing OBD-II Scanner
02
Replace Downstream O2 Sensor

Install new OEM downstream oxygen sensor to restore fast switching response. on the Toyota Camry TRD equipped with 3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust).

Required Tool: 22mm O2 Sensor Socket, Ratchet
03
Clear Trouble Codes

Clear DTCs and drive at 55 mph for 10 miles to set readiness monitors. on the Toyota Camry TRD equipped with 3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust).

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

Equipment for Diagnosing Toyota Camry TRD (P0139)

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Direct-Fit Replacement Part

Toyota Camry TRD OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for Toyota Camry TRD.

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Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

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

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Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

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

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Other Common Fault Codes on Toyota Camry TRD

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Toyota Camry TRD:

4. Toyota Camry TRD P0139 FAQs

What causes code P0139 to trigger on a Toyota Camry TRD?

On the Toyota Camry TRD (3.5L V6 DOHC 24V with Dual VVT-i (301 HP / TRD Cat-Back Exhaust)), P0139 is most frequently caused by Aged and degraded downstream O2 sensor coated in carbon / silicon deposits or Exhaust leak near downstream sensor.

Where is the OBD-II port located on my Toyota Camry TRD?

On the Toyota Camry TRD, the 16-pin DLC diagnostic connector is located Driver footwell lower knee bolster panel. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Toyota Camry TRD with code P0139?

Yes. Safe to drive normally, but will fail emissions inspection. Given that P0139 carries a Low severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.