DTC P0400-00: Exhaust Gas Recirculation "A" Flow; DTC P0401-9C: Exhaust Gas Recirculation "A" Low / Insufficient Flow; DTC P0402-9B: Exhaust Gas Recirculation "A" High/Excessive Flow [12/2023 - ]: Description
WARNING: This page is about a different car, the 2024 Lexus TX 550h+. However, it is still accessible from the selected car via links, so may be relevant.
Based on the driving conditions, the ECM regulates the volume of exhaust gas that is recirculated to each engine cylinder in order to lower the combustion temperature and reduce NOx emissions. The ECM monitors signals such as engine speed, engine coolant temperature, electric load, and vehicle speed. When the EGR permission conditions are met, the ECM controls the opening of the EGR valve linearly through signals to the EGR step motor.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | DTC Output from | Priority | Note |
|---|---|---|---|---|---|---|---|
| P0400-00 | Exhaust Gas Recirculation "A" Flow | During fuel cut, when the change in intake manifold pressure when the EGR valve assembly is operating and when not operating is insufficient (2 trip detection logic). |
|
Comes on | Engine | B | SAE Code: P0400 |
| P0401-9C | Exhaust Gas Recirculation "A" Low / Insufficient Flow | During fuel cut, when the change in intake manifold pressure when the EGR valve assembly is operating and when not operating is insufficient, the intake manifold pressure is less than 54 kPa (7.83 psi) when the EGR valve assembly is not operating (1 trip detection logic). |
|
Comes on | Engine | B | SAE Code: P0401 |
| P0402-9B | Exhaust Gas Recirculation "A" High/Excessive Flow | During fuel cut, when the change in intake manifold pressure when the EGR valve assembly is operating and not operating is insufficient, the intake manifold pressure is 54 kPa (7.83 psi) or more when the EGR valve assembly is not operating (1 trip detection logic). |
|
Comes on | Engine | B | SAE Code: P0402 |