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Vauxhall Zafira 2.0DTI P0400 Code: Exhaust Gas Flow Issue & EGR Valve Diagnosis

Model: Vauxhall Fault Code: P0400 Posted: 2015-08-21 09:23

Hi, I own a Vauxhall Zafira 2.0DTI (52 plate) and recently received a diagnostic code P0400 — 'Exhaust Gas Insufficient Flow Detected' — along with P0400 'Exhaust Gas Recirculation (EGR) Valve Feedback Incorrect Signal'. The car was fitted with a new EGR valve about five weeks ago, and I can confirm it looks like brand-new. While we previously experienced an injector seal issue that has now been resolved, this fault persists. I'm wondering what steps I should take to diagnose or fix the P0400 codes. The car starts reliably in the morning but struggles slightly when starting later in the day. Given that EGR system faults are common in Zafira models, I'm concerned whether the recently replaced EGR valve is still functioning correctly or if another component within the EGR circuit might be at fault. Any advice on how to troubleshoot this issue would be greatly appreciated.

Related fault codes
P0400
Comments (2)
Anonymous 2015-08-21 12:31

A diagnostic code does not necessarily mean a part is faulty. In your case, the P0400 code indicates an EGR flow issue — when the engine commands EGR operation, the CPM (Controlled Pressure Module) detects no flow. This suggests that one or more components in the EGR system may be malfunctioning and should be inspected.

Anonymous 2015-08-21 15:36

Thanks for the clarification. How can I diagnose the root cause? My Zafira starts fine in the morning but has difficulty starting later in the day, which might point to a deeper EGR or fuel system issue. Given that EGR problems are known common faults in this model, I'm checking whether the recently replaced EGR valve is properly installed and functioning correctly.