OBD Guide

P04F2

Catalyst Heater Supply Voltage Bank 1

P04F2 is an OBD-II diagnostic trouble code meaning: Catalyst Heater Supply Voltage Bank 1. Common causes: faulty bank 1 catalyst heater relay, blown heater circuit fuse. Estimated repair cost: $33–167.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$33–167 (est.)

Symptoms

  • Check Engine Light Is On
  • Increased exhaust toxicity during cold start
  • Possible increased warm-up time to meet environmental standards
  • Related Catalytic Converter Error Codes

Causes

  • Faulty Bank 1 Catalyst Heater Relay
  • Blown heater circuit fuse
  • Open or short circuit in the heater power supply circuit
  • Malfunction of the catalyst heating element
  • ECU malfunction

How to Fix

  1. Read error codes and capture freeze frame data
  2. Check the catalyst heater circuit fuse according to the diagram
  3. Check the heater relay for serviceability
  4. Measure the supply voltage at the heater connector
  5. Check the resistance of the heating element
  6. Check wiring for breaks and shorts
  7. Replace faulty elements
  8. Reset the error and check the system operation

Related codes

Error P04F2 by Vehicle Brand

FAQ

What does the P04F2 code mean?

P04F2 is an OBD-II diagnostic trouble code that indicates: Catalyst Heater Supply Voltage Bank 1

What causes a P04F2 error code?

The most common causes of P04F2 include: Faulty Bank 1 Catalyst Heater Relay; Blown heater circuit fuse; Open or short circuit in the heater power supply circuit; Malfunction of the catalyst heating element.

How do I fix a P04F2 diagnostic trouble code?

To fix P04F2: Read error codes and capture freeze frame data. Check the catalyst heater circuit fuse according to the diagram. Check the heater relay for serviceability. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P04F2?

Do not drive — repair immediately

How much does it cost to fix P04F2?

The estimated repair cost for P04F2 is $33–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat