P00B6 on Ford: How to Diagnose & Fix
Radiator Coolant Temperature / Engine Coolant Temperature Correlation
1 Ford model · 1 documented issue · 1 critical · $200-$2,500 repair
P00B6 on Ford by model: symptoms, diagnosis and fix
The 3.5L EcoBoost twin-turbo Transit models experience wastegate actuator sticking, particularly on the passenger-side turbo. Carbon buildup and heat cycling cause the wastegate pivot to seize, resulting in either overboosting (wastegate stuck closed) or underboosting (stuck open). Overboosting triggers an immediate limp mode with reduced power. The issue is more prevalent in Transit vans used for towing or heavy cargo loads that keep the turbos under sustained high heat.
Common Symptoms
- Limp mode / reduced engine power warning
- Check engine light with boost-related codes
- Turbo whistle or flutter noise changes character
- Loss of power under acceleration
- Audible metallic rattle from turbo area at idle
How to Fix
First attempt: remove the wastegate actuator arm and clean the pivot with PB Blaster, then exercise it through full range of motion. Apply high-temp anti-seize to the pivot. If the pivot is corroded beyond cleaning, replace the wastegate actuator assembly ($200-400 per side). In severe cases, the entire turbocharger must be replaced. Preventive maintenance: exercise the wastegate linkage every oil change and avoid extended idle periods that promote carbon buildup.
Sources for this issue (1)
P00B6 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P00B6 mean on a Ford?
P00B6 stands for "Radiator Coolant Temperature / Engine Coolant Temperature Correlation." This code sets when the engine computer sees too large a difference between the radiator coolant temperature sensor and the engine coolant temperature (ECT) sensor. The computer compares these two readings to verify that coolant is flowing properly through the cooling system. When the values do not correlate within the expected range, this code is stored. It can point to a cooling system flow problem, a faulty sensor, or contribute to overheating and reduced fuel economy. On Ford it is documented across 1 model: Transit.
What are the most common causes of P00B6?
The most common causes of P00B6 are: Faulty radiator coolant temperature sensor, Faulty engine coolant temperature (ECT) sensor, Stuck or failed thermostat affecting flow, Low coolant level or air in the cooling system, Wiring or connector fault at either sensor, Restricted coolant flow (clogged radiator or passages), Faulty PCM/ECM (rare). The specific cause varies by vehicle.
How much does it cost to fix P00B6 on a Ford?
Published repair estimates on Ford range from $200 to $2,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P00B6 on a different make?
View P00B6 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.