Mod Details
PremiumNo Difficulty
Mod ID1590
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Linkhttps://evilution.co.uk/mod/p2359-451-cdi-fault.htm Copy to ClipboardOn the 54bhp Smart Fortwo diesel 451, there was yet another issue that caused safe/limp mode. You’ll get the engine warning light come on and the engine will not rev over 3000rpm.
If you bring the codes up on an OBD diagnostics reader, you’ll probably get P2359 or maybe P0234. This relates to incorrect pressure readings for the EGR. According to Chris E, you may see generic error codes between P1041 and P1048 if it’s this valve that’s faulty.
The EGR control vacuum valve is located just behind the throttle body as you stand at the back of the car.
They have a 2 pin electrical connector and 2 vacuum/pressure pipes coming from it.
If you take the throttle body and rubber pipe out of the car, you can access the vacuum valve far more easily. This is what it looks like if you remove the pressure transducer to fit a new one.
What Do They Do?
The vacuum valve sits between a vacuum source or reservoir and a vacuum operated piston. The valve can be electronically opened to allow vacuum to pass.
Do I Need A New One?
Probably not. They are a simple solenoid.
What’s The Fault?
It could have failed but what’s more likely is that a vacuum hose is leaking, the vacuum accumulator is leaking or a check valve is faulty.
What’s The Fix?
Check for leaks using a smoke generator or vacuum leak tester. Look for damaged vacuum hoses and make sure the check valves are functioning.
Vacuum Layout
Vacuum valves = Pink
Vacuum accumulator globe = Red
Check valve = Yellow
EGR valve = Blue
Wastegate actuator = Green
Switching valve = Teal
EGR cooler valve = Orange
The vacuum is generated by the engine in the air inlet manifold and that vacuum is stored in the vacuum accumulator (red) for use even when the engine isn’t creating vacuum. The check valve (yellow) stops the vacuum escaping back into the air inlet manifold. As either of the vacuum valves (pink) open, it allows the vacuum to pass to the appropriate device.
Other Issues
I was contacted by Ryan J who had this P2359 issue and found another reason for the fault.
In his words…
After a long search I found the vacuum valve on top of the engine, going down to the EGR valve had a hole in the vacuum pipe, so was losing vacuum for the whole system and throwing the P2359 code.
There are TWO vacuum valves located at the back of the engine – the top one being for the EGR, and the lower one for the turbo wastegate actuator.
So
Upper vacuum valve circuit = EGR = P2359
Lower vacuum valve circuit = Turbo wastegate = P1041 to P1048
I don’t have a 54bhp CDI currently to be able to check this or add photos. However, it does make sense since the turbo is controlled differently to the 45bhp CDI. The P2359 is a pressure fault so a leaking vacuum pipe could bring this code up.
If you are checking this, please send me photos.