P0402: Exhaust Gas Recirculation Flow Excessive
87 vehicles · 19 makes
P0402 is an OBD-II diagnostic trouble code meaning “Exhaust Gas Recirculation Flow Excessive.” The EGR system is flowing too much exhaust gas, causing rough idle or stalling. This code appears across 87 vehicle models from 19 manufacturers.
Common Causes
Diagnostic Tools
To diagnose P0402, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
Vehicles Affected (87)
G80 Integrated Brake System Weld Defect
12V Auxiliary Battery Drain - All I01 Models
Convertible Top Hydraulic Pump & Cylinder Failure (E64/F12)
Front Suspension Bushing & Control Arm Wear - F48 X1
ZF 8HP Transmission Mechatronic Issues (All 8 Series & M8)
Charging Port & Charge Flap Actuator Failure
Convertible Top Hydraulic Pump Failure - F83 M4 Convertible
DCT Dual-Clutch Transmission Shudder & Clutch Wear - F82/F83 M4
DCT Dual-Clutch Transmission Shudder & Clutch Wear - F87 M2/M2C
B48 Oil Filter Housing Gasket Leak/Cracking
S63 Cooling System Component Failures - E70/F85/F95 X5 M
Coolant Expansion Tank Cracking
xDrive Transfer Case Stress & Fluid Degradation - F97 X3 M / F98 X4 M
Integrated Brake System (IBS) Failure (All 8 Series & M8)
iDrive 8 Software Bugs - Screen Crashes, Reboots & Freezing
IBS Brake System Recall (G06)
Premature Tire Wear (All 8 Series & M8)
xDrive Transfer Case Stress & Fluid Degradation - F98 X4 M / F98 X4 M
Rear Differential Wear & Fluid Degradation - E70/F85/F95 X5 M
48V Mild Hybrid Battery Issues
Oil Leaks - Valve Cover & Oil Filter Housing - F48 X1
DCT Dual-Clutch Transmission Wear & Judder - F10 M5
Oil Leaks - Valve Cover & Oil Filter Housing - All Models
iDrive 8 System Crashes, Reboots & Screen Blank
Phantom Braking & False Forward Collision Warnings
Integrated Hydraulic Brake (IHB) Module Failure
IBS Brake System Recall
Retractable Hardtop Drain Clog & Water Intrusion - E89 Z4
Oil Leaks - Valve Cover & Oil Filter Housing - All Engines
6.7L Power Stroke EGR Cooler Clogging and Failure
6.7L Power Stroke DEF/SCR System Failure - P207F and P20EE Codes
12V Battery Drain and Loss of Drive Power - Recall 24S24 + SSM 53087
Driveshaft Carrier Bearing Failure
360-Degree / Rearview Camera System Failure
6.0L Powerstroke EGR Cooler Rupture and Coolant Leak
8L90 8-Speed Torque Converter Shudder
6T40/6T45 6-Speed Transmission Shudder and Harsh Shifts
9T65 9-Speed Transmission Harsh Shifts and Hesitation
8L45 8-Speed Transmission Torque Converter Shudder
Front Axle Disconnect Actuator and IWE Hub Failure (4WD Engagement Issues)
1.5T CVT Transmission Judder and Valve Body Failure
CVT Shudder/Judder During Acceleration
CVT Shudder/Judder During Acceleration
IMA Hybrid Battery Pack Failure and Reduced Performance
Premature Engine Mount Failure Causing Vibration
Hybrid Inverter/Power Control Unit (PCU) Cooling System Failure
Hybrid Power Loss While Driving
Type R Limited Slip Differential Noise and Chattering
Sunroof/Hatch Water Leaks (SC Models)
Soft Top Tears and Rips
Tailgate/Liftgate Hinge and Lift Support Problems
Electrical System Issues and Starter Failures
IMA Hybrid Battery Failure (All Generations)
ICCU Failure and 12V Battery Drain
Hybrid High-Voltage Battery Degradation
Headlight and Taillight Moisture Condensation
Regenerative Braking Loss and Reduced Braking Power
Onboard Charger (OBC) Failure (Niro EV)
Subframe and Underbody Rust / Corrosion
Rear Brake Caliper Seizing / Parking Brake Cable Corrosion
Rear Brake Caliper Seizing
Rear Brake Noise and Premature Wear
Mass Airflow (MAF) Sensor Failure
A/C Condenser Leak
EGR Valve and Passage Carbon Buildup
EGR Valve Carbon Buildup and Coolant Leak (SkyActiv 2.5L)
Battery Pack Capacity Degradation
Concentric Slave Cylinder (CSC) Failure
Coolant Leak from Thermostat Housing (VQ35DE)
A/C Compressor Failure
Cam Tower Oil Leak
Hybrid Battery Pack (HV Battery) Failure
Dashboard Cracking and Melting
Frame Rust and Corrosion
Hybrid Battery Pack Degradation and Failure
6-Speed Automatic Transmission Torque Converter Shudder
KDSS (Kinetic Dynamic Suspension System) Hydraulic Leaks
EGR System Carbon Buildup Causing Rough Idle and Stalling
EGR Cooler Cracking and Coolant Leak
EGR Cooler and Valve Clogging with Carbon Deposits
EA888 Plastic Water Pump and Thermostat Housing Failure
EA888 Water Pump and Thermostat Housing Failure
Water Pump/Thermostat Housing Failure
Plastic Water Pump and Thermostat Housing Leak
8-Speed Automatic Transmission Rough Shifting and Shudder
Rear Taillight Seal Water Intrusion
FAQ
What does P0402 mean?
P0402 stands for "Exhaust Gas Recirculation Flow Excessive." The EGR system is flowing too much exhaust gas, causing rough idle or stalling.
What are the most common causes of P0402?
The most common causes of P0402 are: EGR valve stuck open, Faulty EGR pressure sensor, Vacuum leak to EGR valve, Carbon holding EGR valve open, ECU calibration issue. The specific cause varies by vehicle.
How much does it cost to fix P0402?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P0402?
Au7o has documented P0402 across 87 vehicle models from 19 manufacturers: Audi, BMW, Cadillac, Chrysler, Dodge, Ford, GMC, Honda, Hyundai, Jeep, Kia, Land Rover, Mazda, Nissan, RAM, Subaru, Toyota, Volkswagen, Volvo.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.