OBD
OBDIICSU

P0479

Severity: Low

Exhaust Pressure Control Valve Intermittent

Last updated: July 2026

System
Powertrain
Subsystem
Auxiliary Emission Controls
Code Type
Generic (SAE)

What does P0479 mean?

P0479 is a generic (SAE) powertrain diagnostic trouble code. It is defined as "Exhaust Pressure Control Valve Intermittent". It falls under the auxiliary emission controls area of the vehicle’s powertrain system, and has the same core meaning across most makes and models.

When is P0479 set?

The onboard diagnostic system sets P0479 when it detects a condition matching "exhaust pressure control valve intermittent" in the auxiliary emission controls circuit or system. When the fault is confirmed, the module stores the code and, in most cases, turns on a warning light.

This code is generally minor and often relates to a signal, range or performance condition. It should still be inspected, especially if it returns after clearing.

Common symptoms

Possible causes

What to check first

  1. Scan for all stored and pending codes and note the freeze-frame data
  2. Inspect the wiring and connectors for the affected circuit
  3. Check for related leaks, loose components or obvious damage
  4. Test the relevant sensor and its reference/ground with a meter
  5. Clear the code and retest to see whether it returns

Frequently asked questions

What does the P0479 code mean?

P0479 means "Exhaust Pressure Control Valve Intermittent". It is a generic powertrain trouble code in the auxiliary emission controls area.

Is it safe to drive with a P0479 code?

This code is usually minor, and short-distance driving is often possible, but you should still have it checked — especially if the warning light stays on or the code returns.

How do I fix a P0479 code?

There is no single fix. Start by confirming the code with a scan tool, then work through the likely causes and checks above — inspecting wiring, connectors and the relevant components before replacing any parts. On most vehicles, confirm the diagnosis before repairs.

Can I clear the P0479 code myself?

You can clear the code with an OBD-II scan tool, but if the underlying fault is still present it will usually return. Clearing without repair is only useful to confirm whether the fault is active.

Related codes

Important

This information is provided for general reference only. It is not repair advice and may not apply to every make or model. Manufacturer-specific codes can differ. Always confirm a diagnosis with a scan tool and, where needed, a qualified technician before replacing parts.