OBD Guide

P2B79

Coolant Heater B Control Circuit Performance

P2B79 is an OBD-II diagnostic trouble code meaning: Coolant Heater B Control Circuit Performance. Common causes: coolant heater malfunction, problems in the electrical circuit (open or short circuit). Estimated repair cost: $28–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$28–89 (est.)

Symptoms

  • Extended engine warm-up time
  • Less efficient interior heating
  • Check Engine Light Illuminates
  • Possible errors in related systems
  • Reduced coolant temperature in cold weather

Causes

  • Coolant heater malfunction
  • Problems in the electrical circuit (open or short circuit)
  • Faulty relay or fuse
  • Problems with the control unit
  • Corrosion of contacts or connectors

How to Fix

  1. Check heater circuit fuses and relays
  2. Inspect the electrical circuit for damage
  3. Check heater resistance
  4. Check connectors and contacts for oxidation
  5. If necessary, replace the coolant heater

Related codes

Error P2B79 by Vehicle Brand

FAQ

What does the P2B79 code mean?

P2B79 is an OBD-II diagnostic trouble code that indicates: Coolant Heater B Control Circuit Performance

What causes a P2B79 error code?

The most common causes of P2B79 include: Coolant heater malfunction; Problems in the electrical circuit (open or short circuit); Faulty relay or fuse; Problems with the control unit.

How do I fix a P2B79 diagnostic trouble code?

To fix P2B79: Check heater circuit fuses and relays. Inspect the electrical circuit for damage. Check heater resistance. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2B79?

Yes, but get it checked soon

How much does it cost to fix P2B79?

The estimated repair cost for P2B79 is $28–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat