P2BAD on Land Rover
NOx Exceedance - SCR Catalyst Conversion Efficiency
P2BAD on Land Rover vehicles indicates nox exceedance - scr catalyst conversion efficiency. Au7o has documented this code across 1 Land Rover model — most commonly on Discovery. This code, found on modern diesels with selective catalytic reduction (SCR), means the system has detected that tailpipe NOx (nitrogen oxide) emissions have exceeded the legal limit because the SCR catalyst isn't converting them efficiently enough. The SCR system injects diesel exhaust fluid (DEF/AdBlue) over a catalyst to chemically break down NOx, and NOx sensors before and after the catalyst measure how well it's working. When the measured conversion falls below the required threshold, the computer flags this code, often triggering warning lights, a countdown to reduced power, or limp mode. Common roots are contaminated or low-quality DEF, a degraded catalyst, or faulty NOx sensors. Typical repair costs on Land Rover range from $2,000 to $5,000, depending on the specific model and root cause.
Common Causes of P2BAD
- •Contaminated, diluted, or low-quality diesel exhaust fluid (DEF)
- •Faulty NOx sensor (upstream or downstream)
- •Degraded, aged, or contaminated SCR catalyst
- •Faulty or clogged DEF/reductant injector
- •Insufficient DEF dosing or low DEF quantity
- •Exhaust leak before or within the SCR system
- •Faulty EGR system raising engine-out NOx
- •Wiring or connector faults to NOx sensors
P2BAD on Land Rover by Model
Land Rover Discovery(1 issue)
- EGR Cooler Failure and Coolant Leak (TDV6/SDV6)2010-2018
The EGR cooler on the 3.0L TDV6 and SDV6 diesel engines develops internal cracks that allow coolant to leak into the exhaust system. This causes white smoke from the exhaust, gradual coolant loss, and can contaminate the DPF. In the worst case, coolant enters the combustion chambers and causes hydrolock. This is considered one of the most serious diesel Discovery failures.
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View P2BAD across all makes →Frequently Asked Questions
What does P2BAD mean on Land Rover?▼
P2BAD stands for "NOx Exceedance - SCR Catalyst Conversion Efficiency." This code, found on modern diesels with selective catalytic reduction (SCR), means the system has detected that tailpipe NOx (nitrogen oxide) emissions have exceeded the legal limit because the SCR catalyst isn't converting them efficiently enough. The SCR system injects diesel exhaust fluid (DEF/AdBlue) over a catalyst to chemically break down NOx, and NOx sensors before and after the catalyst measure how well it's working. When the measured conversion falls below the required threshold, the computer flags this code, often triggering warning lights, a countdown to reduced power, or limp mode. Common roots are contaminated or low-quality DEF, a degraded catalyst, or faulty NOx sensors. On Land Rover specifically, this code is documented across 1 model.
What causes P2BAD on Land Rover vehicles?▼
Common causes on Land Rover: Contaminated, diluted, or low-quality diesel exhaust fluid (DEF), Faulty NOx sensor (upstream or downstream), Degraded, aged, or contaminated SCR catalyst, Faulty or clogged DEF/reductant injector, Insufficient DEF dosing or low DEF quantity. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P2BAD on a Land Rover?▼
Repair costs on Land Rover range from $2,000 to $5,000, depending on the specific model and root cause.
Which Land Rover models have P2BAD documented?▼
Au7o has documented P2BAD on 1 Land Rover model: Discovery.