P0159 Toyota Sequoia – Oxygen Sensor Circuit Slow Response (Bank 2 Sensor 2)

Toyota-specific code — factory diagnostic data

Last updated: May 31, 2026

Definition source: Toyota factory description. Diagnostic guidance is based on factory-defined fault logic for this code.

P0159 on the 2014 Toyota Sequoia means: Oxygen Sensor Circuit Slow Response (Bank 2 Sensor 2). It is a circuit code reported by the SFI System.

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P0159 Quick Answer

P0159 on a 2014 Toyota Sequoia indicates Oxygen Sensor Circuit Slow Response (Bank 2 Sensor 2). Start with a freeze-frame check and a careful inspection of the connector and wiring at the affected device before replacing any parts.

What Does P0159 Mean on a Toyota Sequoia?

On the 2014 Toyota Sequoia, the SFI System sets P0159 when it detects a fault matching its official definition: Oxygen Sensor Circuit Slow Response (Bank 2 Sensor 2). This is a manufacturer-specific definition from Toyota factory diagnostic data and applies to the XK60-generation Sequoia.

Symptoms

• Warning light for the affected system (check engine, ABS, airbag, or a system indicator depending on the module)
• Reduced or lost function of the sfi system
• Possible related codes from other modules on the Sequoia CAN/LIN network

Common Causes

• Fault in the component named in the definition (oxygen sensor circuit slow response (bank 2 sensor 2))
• Open, shorted, or high-resistance wiring in the affected circuit
• Connector corrosion, water ingress, or a backed-out terminal
• Loss of supply voltage or a poor ground at the device
• Module internal fault — confirm wiring and supplies before condemning the module

Diagnostic Approach

For P0159 on the 2014 Toyota Sequoia you’ll want an OBD-II scan tool with live-data and freeze-frame support (a Toyota Techstream-class tool reads enhanced data), plus a digital multimeter and the wiring diagram.

• Confirm the code is current, not stored history, and record freeze-frame data.
• Read all modules — related codes often pinpoint the root cause faster than the headline code.
• Inspect and wiggle-test the connector at the named device while watching live data.
• Measure supply voltage and ground integrity at the device; verify the circuit against the Sequoia wiring diagram.
• Substitute or isolate the suspect device only after wiring and supplies check out.
• Clear the code and road-test through one or two drive cycles to confirm the repair.

Possible Fixes

• Repair open/short/high-resistance wiring or a corroded connector
• Restore supply voltage or ground at the affected device
• Replace the failed component named in the definition
• Replace and, where required, initialise/program the module if it is internally faulty

Can I Still Drive With P0159?

It depends on the system. SFI System faults that affect braking, the airbag/restraint system, power steering, or stability control should be repaired before further driving. Comfort or convenience faults can usually be deferred briefly, but related codes can mask one another on the Sequoia network — diagnose promptly.

Source

Code definition from 2014 Toyota Sequoia (XK60) factory diagnostic information (SFI System). Symptom, cause, and diagnosis guidance summarised from standard OBD-II diagnostic practice for this platform.