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Discussion Starter · #1 ·
I've got n 0202 Reg vectra SRI DTI and engine warning kept coming on and it was losing power I have had the fault code tested and it comes back with "egr flow" egr valve is working fine. cleaned out inlet mainfold.

but no joy...

any idea's


Premium Member
563 Posts
i found this,i don't know if its your problem though.
Hi All,

I’ve recently had the P0400 code on my 2001 2.0L DTI Vectra. I managed to fix the problem though after a series of checks (which I’ve outlined below). These might not fix all P0400 problems, but I hope they’ll offer solutions to at least a few.

(1) Engine management warning light comes on at idle speeds after engine has warmed up. Results in loss of engine power. Light goes out after a speed of 30-35 mph is reached.
(2) Engine management warning light comes on after deceleration from speed (e.g. leaving the motorway onto the slip-road). Results in loss of engine power.
(3) Engine management warning light comes on when reverse gear selected. This may be linked to light coming on at idle speeds

Code description:
The P0400 code description is – Exhaust Gas Recirculation (EGR) Flow Malfunction. It states that potential faults include

• Blocked pipework
• Faulty EGR valve
• Faulty EGR solenoid
• Faulty wiring
• Faulty ECM

Most of the checks can be carried out without too much trouble (apart from the lack of working space within the engine compartment. It’s worth testing to see if the fault is cured after each of the checks.

(1) Check all rubber connectors on the pipework which supply the 3 vacuum valves. Two vacuum valves are located at the right hand side of the battery, and the other is located towards the top left hand corner of the engine bay – by the turbo-charger. The rubber connectors split with age. I found two split, and replaced them.
(2) Check all vacuum pipes for damage/blockage. I suggest you remove each pipe in turn and inspect thoroughly for damage. Also blow through each pipe to remove any blockages. Pay particular attention to where the pipes are routed between the battery and the engine – the pipes are known to wear significantly in this area. At first, I tried to inspect all pipes in situ; this caused me to miss damaged pipework on my first run through of the checks. Therefore, I suggest you remove each pipe in turn to prevent this.
(3) Check the filters at the bottom of each vacuum valve for blockage. Each vacuum valve has a filter fitted via a rubber connector on the underside of the valve. Remove the filter and check for blockages (I simply blew through the removed filter)
(4) Check the EGR valve is not clogged. The EGR valve sits on the front of the engine block. If you remove the plastic engine cover (3 torks screws) you will find the EGR valve right at the front of the engine on the inlet manifold. To me it looked like I would need a special tool to remove the 2 screws that secure the EGR valve, but I found that an 11mm socket just about fitted. When I removed my EGR valve I found it coated in a thick oily sludge. I wiped off most of this with rags, but some of the debris was baked on hard. I carefully removed this by scraping with a small flat bladed screwdriver. Once clean, it’s worth checking the valve movement. Do this initially by pressing between the palms of both hands (the valve stem should move in & out a few mm when you do this). Also, you can check the valve diaphragm isn’t damaged by sucking on the inlet port of the valve. Again, the valve stem should move in & out a few mm when you do this. If the EGR valve is faulty you should be able to get one from your local scrapyard for about £40.

At this point it’s also worth checking that where the valve seats within the manifold is clean. I found a few deposits on mine that I scrapped free with a screwdriver.
(5) Check the electrical connections on all vacuum valves. As a precaution, I removed all connectors and squirted with WD40.
(6) Change the vacuum valves in turn. On my Vectra there were two types of valves – one black one and two grey ones. They grey ones are a different part number to the black ones, and they can’t be interchanged. If you contact Vauxhall for these valves, they’ll charge you about £115 per valve. Valves can be obtained from your local car breaker though for about £10 each. I suggest you quote the part number to your local scrap dealer when you ring up though, as it may save you a few wasted journeys.
(7) Replace the solenoid relays which control the vacuum valves. These are located in the electrical control box just above the battery on the RHS of the engine bay. My local scrap merchant donated these for free.
(8) Replace the Mass Air Flow Sensor (MAF) – I didn’t have to do this

I actually checked through (1) through (7) of the items listed above, but I think the problem was actually caused by a combination of (1), (2) and (4).

Anyway, hope this helps.


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