Reference meaning
What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
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A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Scan worksheet →Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
P0400EGR “A” FLOW
Manufacturer communications
18Original wording in English
MITSUBISHI
This Technical Service Bulletin provides instructions to reprogram the ECU with the countermeasure software when the check engine light illuminates with DTC of P0401/ P0400.
SUBARU
This bulletin announces the availability of reprogramming files to optimize the Engine Control Module (ECM) for hard starting in sub-freezing temperatures, DTC P0400, and surging in high altitudes.
SUBARU
This bulletin announces availability of reprogramming files to optimize the Engine Control Module (ECM). These new files address concerns of the check engine light coming on and setting a DTC P0400: EGR “A” FLOW. The DTC can set if the ECM tests the EGR system when ambient / intake air temperatures are below freezing.
FORD
SOME 2014-2016 TRANSIT CONNECT VEHICLES EQUIPPED WITH THE 2.5L ENGINE MAY EXHIBIT A CONSTANT OR INTERMITTENT ILLUMINATED MIL WITH VARIOUS DRIVABILITY ISSUES AND ONE OR MORE OF THE FOLLOWING DTCS: P0010, P0103, P0104, P0122, P0131, P0135, P0137, P0141, P0201-P0204, P0217, P0222, P0223, P025A, P0300, P0301-P0304, P0316, P0351-P035…
Check vehicle applicability
82A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Buick | ROADMASTER ↗ | 1996 |
| Cadillac | FLEETWOOD ↗ | 1996 |
| Chevrolet | CAMARO ↗ | 1997 |
| Chevrolet | CAMARO ↗ | 1996 |
| Chevrolet | CAPRICE ↗ | 1996 |
| Chevrolet | IMPALA ↗ | 1996 |
| Chevrolet | W3500 ↗ | 2005 |
| Chevrolet | W4500 ↗ | 2005 |
Code meaning and manufacturer information
Original wording in English · Historical directory labels; manufacturer applicability has not been established for every entry.
Exhaust Gas Recirculation Flow Malfunction
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.