P0404 on Cadillac
Exhaust Gas Recirculation Circuit Range/Performance
P0404 on Cadillac vehicles indicates exhaust gas recirculation circuit range/performance. Au7o has documented this code across 3 Cadillac models — most commonly on CTS, CTS-V, Escalade. This code means the exhaust gas recirculation (EGR) system isn't performing within its expected range. The EGR valve routes a metered amount of exhaust gas back into the intake to lower combustion temperatures and reduce nitrogen-oxide emissions, and the computer monitors the valve's actual position versus what it commanded. When the valve sticks, moves incorrectly, or the feedback doesn't match the command, P0404 sets. This can cause rough idle, hesitation, pinging, and increased emissions. Typical repair costs on Cadillac range from $800 to $3,500, depending on the specific model and root cause.
Common Causes of P0404
- •Carbon buildup clogging the EGR valve or passages
- •Sticking or failed EGR valve
- •Faulty EGR position sensor
- •Corroded or loose EGR connector
- •Damaged or shorted EGR wiring
- •Vacuum leak or failed vacuum control (on vacuum-operated systems)
- •Clogged EGR cooler or tubes
- •Faulty PCM/ECM (rare)
P0404 on Cadillac by Model
Cadillac CTS(1 issue)
- Electric Power Steering Rack Failure2008-2013
The 2nd generation CTS (2008-2013) uses an electric power steering rack that can fail, causing heavy or intermittent steering assist. The electric motor integrated into the steering rack wears out, or the steering control module loses communication. Symptoms include sudden loss of power steering assist (steering becomes very heavy), intermittent assist that cuts in and out, and steering warning lights. The entire rack assembly must be replaced as the motor is not serviceable separately.
Cadillac CTS-V(1 issue)
- Magnetic Ride Control Shock Failure2009-2019
The CTS-V (2nd and 3rd gen) comes standard with Magnetic Ride Control (MRC) shocks that use magnetorheological fluid to adjust damping. These expensive shocks have a limited lifespan, typically 60,000-100,000 miles, after which the MR fluid degrades and the shocks either become too stiff, too soft, or leak. Replacement with OEM MRC shocks is very expensive ($500-800 per shock). Many owners switch to traditional high-performance shocks to avoid the recurring cost.
Cadillac Escalade(1 issue)
- Air Suspension / Magnetic Ride Control Compressor Failure2007-2020
The Cadillac Escalade with Autoride (air suspension) or Magnetic Ride Control uses an air compressor and electronic shocks that commonly fail between 80,000-120,000 miles. The air compressor burns out from continuous cycling caused by slow air leaks in the air springs (bags). Failed air springs cause the vehicle to sag at one or more corners, and the compressor overworks trying to compensate. The Magnetic Ride Control shocks contain magnetorheological fluid that degrades over time, causing a harsh or bouncy ride. Common on 2007-2014 (3rd gen) and 2015-2020 (4th gen) Escalades equipped with these options.
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View P0404 across all makes →Frequently Asked Questions
What does P0404 mean on Cadillac?▼
P0404 stands for "Exhaust Gas Recirculation Circuit Range/Performance." This code means the exhaust gas recirculation (EGR) system isn't performing within its expected range. The EGR valve routes a metered amount of exhaust gas back into the intake to lower combustion temperatures and reduce nitrogen-oxide emissions, and the computer monitors the valve's actual position versus what it commanded. When the valve sticks, moves incorrectly, or the feedback doesn't match the command, P0404 sets. This can cause rough idle, hesitation, pinging, and increased emissions. On Cadillac specifically, this code is documented across 3 models.
What causes P0404 on Cadillac vehicles?▼
Common causes on Cadillac: Carbon buildup clogging the EGR valve or passages, Sticking or failed EGR valve, Faulty EGR position sensor, Corroded or loose EGR connector, Damaged or shorted EGR wiring. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0404 on a Cadillac?▼
Repair costs on Cadillac range from $800 to $3,500, depending on the specific model and root cause.
Which Cadillac models have P0404 documented?▼
Au7o has documented P0404 on 3 Cadillac models: CTS, CTS-V, Escalade.