OBD-II Code
P0474
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$20–$500
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$20 (tube cleaning) to $500 (sensor + harness + active regen).
P0474 means the Exhaust Back Pressure sensor signal is intermittent — the ECM saw the voltage drop in or out of range briefly enough to fail the rationality test but not long enough to set a hard P0472 or P0473.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0474 means the Exhaust Back Pressure sensor signal is intermittent — the ECM saw the voltage drop in or out of range briefly enough to fail the rati…
P0474 means the Exhaust Back Pressure sensor signal is intermittent — the ECM saw the voltage drop in or out of range briefly enough to fail the rationality test but not long enough to set a hard P0472 or P0473. Intermittent codes are the worst category to chase because the fault isn't present when the truck is on the lift.
Cheapest-first ladder
- Wiggle-test the EBP sensor harness with engine running and scan tool watching the live PID — flex the connector, tug the pigtail, tap the sensor body with a screwdriver handle. Any blip or dropout in the live reading localizes the fault to that mechanical point.
- Check the connector for moisture migration — diesel EBP connectors are heat-soaked and live in spray-zone real estate; water wicks down the wires via capillary action and corrodes the pins from inside. Pull the connector, blast it with electronics cleaner, dry it, and re-grease with Stabilant 22 or dielectric grease.
- Compare live EBP data against expected ranges across a 20-minute drive cycle: naturally-aspirated gas should sit 0-10 psi from idle to WOT; turbo gas 5-30 psi under boost; diesel 30-50 psi at full load. Intermittent dropouts to 0 or jumps to 80+ psi are the data signature.
- Inspect the EBP pressure tube on diesels — a partially-clogged tube passes some pressure but dampens transients enough to fail the rationality check intermittently. Expensive-misdiagnosis caveat: diesel EBP sensor tubes that are 70% clogged behave exactly like a flaky sensor — the tube passes static pressure fine but can't follow the dynamic pressure pulses during boost transitions, so the sensor reads correctly at idle and intermittently wrong under load. Clean the tube before swapping the sensor; a $20 cleaning saves the $300 part nine times out of ten.
Vehicle-specific patterns2003-2007 Ford 6.0L Powerstroke throws P0474 as the first symptom of a partially-soot-clogged EBP tube — the truck runs fine at idle and during easy…
- 2003-2007Ford 6.0L Powerstroke throws P0474 as the first symptom of a partially-soot-clogged EBP tube — the truck runs fine at idle and during easy cruise but the code sets every time the driver merges onto the highway under load.
- 2008-2010Ford 6.4L Powerstroke shows the same pattern but adds the wrinkle that the EBP sensor reading drives DPF regen logic — a flaky EBP signal causes the truck to skip or abort active regens, which accelerates DPF loading.
- 2011-2016Duramax LML reports EBP intermittents most often when the differential-pressure hose at the DPF cracks at the heat-shielded elbow — inspect both pressure tubes for cracks before condemning the sensor.
- 2013-2018RAM Cummins 6.7L EBP intermittents typically trace to a harness chafe at the exhaust brake actuator bracket where heat cycling fatigues the wire jacket.
- 2010-2015VW 2.0 TDI EA189 differential-pressure intermittents usually come from cracked hose elbows at the DPF tap points. Common diesel concern: soot-bound EBP plumbing from extended highway non-regen cruise dampens dynamic pressure transients and reads as intermittent fault — run an active regen via scan tool first.
Estimated repair$20 (tube cleaning) to $500 (sensor + harness + active regen).
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