P046C on Ford: How to Diagnose & Fix
Exhaust Gas Recirculation Sensor "A" Circuit Range/Performance
1 Ford model · 1 documented issue · 1 critical · $1,500-$3,500 repair
P046C on Ford by model: symptoms, diagnosis and fix
The 2011-2016 F-350's 6.7L Power Stroke uses an EGR cooler that is subjected to thermal cycling between roughly 1,200 F exhaust gas and 200 F coolant. Repeated expansion and contraction fatigues the cooler core and it cracks internally, letting coolant into the exhaust stream. Owners see gradual coolant loss with no external leak, white sweet-smelling smoke (most obvious on a warm restart or under acceleration), and eventually overheating. Trucks that idle for long periods or tow heavy - the typical F-350 dually or chassis cab duty cycle - fail earliest.
Common Symptoms
- Unexplained coolant loss
- White sweet-smelling exhaust smoke on warm restart or under throttle
- Rough cold start
- Overheating while towing
- Low coolant warning with no visible leak
How to Fix
Diagnose with a cooling system pressure test and by checking for exhaust gas in the coolant; do not assume a head gasket before checking the EGR cooler. Replace the EGR cooler, along with the EGR valve if it is fouled, and flush the cooling system. Inspect the passenger-side cylinder head at the same time, as it can be cracked on early 2011-2012 engines presenting with the same coolant loss. There is no recall for the EGR cooler; some trucks were covered under the 5-year/100,000-mile diesel powertrain warranty when new.
Sources for this issue (2)
P046C 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 P046C mean on a Ford?
P046C stands for "Exhaust Gas Recirculation Sensor "A" Circuit Range/Performance." This code means the engine computer found that the signal from the exhaust gas recirculation (EGR) position/flow sensor is out of its expected range or not changing the way it should compared with commands. The EGR system routes a measured amount of exhaust back into the intake to lower combustion temperatures and reduce emissions, and this sensor reports how far the valve is open or how much gas is flowing. An implausible reading suggests the sensor, the valve it monitors, or the wiring is not performing correctly, which can affect emissions and sometimes idle quality. On Ford it is documented across 1 model: F-350.
What are the most common causes of P046C?
The most common causes of P046C are: Faulty EGR position or flow sensor, Carbon buildup clogging the EGR valve or passages, Sticking or failing EGR valve, Damaged, corroded, or loose sensor wiring/connector, Bent or pushed-out connector terminals, Vacuum or exhaust leak affecting EGR flow, PCM fault (rare). The specific cause varies by vehicle.
How much does it cost to fix P046C on a Ford?
Published repair estimates on Ford range from $1,500 to $3,500 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.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.