M A P sensor

[Carol Anne]

Car been acting up a bit lately, ie: intermittent rough idling at lights etc, as if it was about to stall, and sometimes lack of power when accelerating. Took to Rover who connected up to computer and diagnosed faulty MAP sensor, fine, 220 quid please Carol Anne and off you go.

Got three miles down the road and same thing started again! Righ, back to Rover, and sent me out on the road with a very nice young man, and yes you've guessed it.... no problems, then 100yds from the garage it acted up. Back into the workshop and this time took all the baffle off and discovered a air leak on a vacuum pipe. This fixed and the car has run perfectly for the past week. Which leads me to ask,,,,

Is that leak likely to have been responsible and not the sensor? could that leak have caused the fault codes to indicated the sensor? and really shouldn't they have checked for something like that in the first place? I sort of mentioned this to the service manager, but I have this stupid female complex about garages that I just end up feeling like an idiot, and palmed off with the excuse that the bad pipe would have caused the sensor to fail anyway.

Sorry this is so long winded, but if anyone could throw some light on this I'd be most grateful

[Toureman]

I think the garage has tried to cover up their big costly mistake.

An air leak in a vacum pipe would cause the symtoms you described!

I think you should ask for the first unescasary �220 back!

Try getting advice from the AA or your local Citizens advice.

[Andy Boz]

I fully agree with previous post. Firstly read the definition of MAP sensor,

Definition: Refers to a manifold absolute pressure sensor, a variable resistor used to monitor the difference in pressure between the intake manifold at outside atmosphere.

This information is used by the engine computer to monitor engine load (vacuum drops when the engine is under load or at wide open throttle). When the engine is under load, the computer may alter spark timing and the fuel mixture to improve performance and emissions.

Or, in laymans terms, it tells the brain how much suck is in the inlet manifold, where, conveniently is the vacuum pipe that you mentioned. I would demand a refund of the cost of the new sensor, as they have misdiagnosed the fault, and therefore ripped you off, for something you didn't need, and were told you did. Regards

Andy

[Carol Anne]

thanks for the advice guys, I still have the old sensor, so Im going ask for my money back on the new one.

[loola]

Hi Carol Anne,

I totally agree with the last 2 posts. About a month ago my auntie was having the same symptoms as you have described on her renault scenic. Once plugged into the diagnostic scanner, a few fault codes appeared - one of them being the MAP sensor. The first thing that the mechanic checked was the vacuum pipe, and guess what?.... it was slightly split at the end. A simple snip of approx 10mm of the corroded pipe and then reconnection cured the problem. The other fault codes were triggered off by this one pipe being faulty. Now all is fine and it cost her �10!
DEFINATELY go back to the dealer and demand a full refund from them. Good luck, let us know how you get off!

[Carol Anne]

Im going to email a link to this page to the manager up there!!

[NashC24]

Hi can this MAP sensor cause the feul injector PC to break? Please help by scenic is given the same faults and the dealer wants to rip me off

[NashC24]

Same thing ha[ppened to me can the MAPsensor cause the Injector computer to pack in?