OBD Guide

P2B74

Coolant Heater A Control Circuit High

P2B74 is an OBD-II diagnostic trouble code meaning: Coolant Heater A Control Circuit High. Common causes: coolant heater malfunction, open or short circuit in control circuit. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Malfunction of the coolant heating system
  • Cold air from the interior heating system at low temperatures
  • Extended engine warm-up time
  • The Check Engine light comes on

Causes

  • Coolant heater malfunction
  • Open or short circuit in control circuit
  • Problems with the heater relay
  • Engine control unit malfunction
  • Corrosion of contacts or connectors

How to Fix

  1. Checking and testing the coolant heater
  2. Checking the integrity of the heater control circuit
  3. Heater relay diagnostics
  4. Checking contacts and connectors for corrosion
  5. Reflashing or replacing the control unit if necessary

Related codes

Error P2B74 by Vehicle Brand

FAQ

What does the P2B74 code mean?

P2B74 is an OBD-II diagnostic trouble code that indicates: Coolant Heater A Control Circuit High

What causes a P2B74 error code?

The most common causes of P2B74 include: Coolant heater malfunction; Open or short circuit in control circuit; Problems with the heater relay; Engine control unit malfunction.

How do I fix a P2B74 diagnostic trouble code?

To fix P2B74: Checking and testing the coolant heater. Checking the integrity of the heater control circuit. Heater relay diagnostics. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2B74?

Yes, but get it checked soon

How much does it cost to fix P2B74?

The estimated repair cost for P2B74 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat