P2B78
Coolant Heater B Control Circuit High
P2B78 is an OBD-II diagnostic trouble code meaning: Coolant Heater B Control Circuit High. Common causes: open or short circuit in the heater circuit, coolant heater malfunction. Estimated repair cost: $28–89.
Symptoms
- Extended engine warm-up time in cold weather
- Check Engine Light Illuminates
- Reduced engine efficiency at low temperatures
- Possible errors of related systems
Causes
- Open or short circuit in the heater circuit
- Coolant heater malfunction
- Problems with the relay or circuit fuse
- Control module malfunction
- Corroded contacts or damaged connectors
How to Fix
- Check heater circuit fuses and relays
- Diagnose the integrity of wiring and connectors
- Check the resistance of the heating element
- Scan the control module for other errors
- If necessary, replace the coolant heater
Related codes
Error P2B78 by Vehicle Brand
FAQ
What does the P2B78 code mean?
P2B78 is an OBD-II diagnostic trouble code that indicates: Coolant Heater B Control Circuit High
What causes a P2B78 error code?
The most common causes of P2B78 include: Open or short circuit in the heater circuit; Coolant heater malfunction; Problems with the relay or circuit fuse; Control module malfunction.
How do I fix a P2B78 diagnostic trouble code?
To fix P2B78: Check heater circuit fuses and relays. Diagnose the integrity of wiring and connectors. Check the resistance of the heating element. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P2B78?
Yes, but get it checked soon
How much does it cost to fix P2B78?
The estimated repair cost for P2B78 is $28–89. Actual cost depends on your vehicle, location, and labor rates.
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