P0407 means the EGR position sensor 'B' is sending a voltage below the normal operating range. Sensor B exists on engines with dual EGR valves (V6 and V8 diesels) or on petrol engines that use a primary and secondary feedback sensor. The fault is almost always wiring or a failed sensor shorted to ground.
P0407 means the EGR position sensor 'B' is sending a voltage below the normal operating range. Sensor B exists on engines with dual EGR valves (V6 and V8 diesels) or on petrol engines that use a primary and secondary feedback sensor. The fault is almost always wiring or a failed sensor shorted to ground.
P0407 is a emissions-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P0407 and illuminates the check engine light.
If your vehicle has triggered P0407, you may notice one or more of these symptoms:
Here are the most common causes of P0407, ranked by how likely they are to be the culprit:
Generally yes, for short-term driving. Driveable. P0407 affects the second EGR position sensor (sensor B), present on engines with dual EGR valves or dual feedback sensors. The ECU loses confidence in EGR position feedback and may disable EGR or enter limp mode on diesels. Failed emissions test is guaranteed.
Follow these steps to pinpoint the root cause of P0407:
Repair costs for P0407 vary depending on the root cause and your vehicle. Here are typical estimates:
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0407 behaves differently depending on your vehicle. Select your car below for model-specific causes, known issues, and adjusted cost estimates:
These codes are often seen alongside P0407 or indicate related issues:
Sensor A is the primary EGR position feedback. Sensor B is the secondary, present on engines with two EGR valves (most V6/V8 diesels) or on engines that use a redundant feedback sensor. On most 4-cylinder engines there is no sensor B, so P0407 only appears on more complex setups (Audi 3.0 TDI V6, Mercedes V6 diesels, some BMW B57).
Short-term yes. The ECU disables the affected EGR bank and falls back on the other bank, causing uneven idle and reduced power. Diesels may enter limp mode. Plan the repair within a couple of weeks to avoid carbon buildup or DPF problems.
Usually no. P0407 on a 4-cylinder engine usually means the workshop manual labels the existing single sensor as 'B' due to manufacturer convention, or the engine has a primary plus secondary feedback (rare). On VW EA189/EA288, BMW N47/B47, and Mercedes OM651, the relevant code is normally P0405 not P0407.
Yes, in most cases. EGR sensor or valve replacement is far cheaper than dealing with a clogged DPF, NOx sensor faults, or AdBlue limp-mode countdown that result from continued EGR failure. On Audi 3.0 TDI V6 with dual EGR, budget for both sides to be inspected, since one failure often signals the other is close behind.
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