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I have a code just set for the first time yesterday

sure yesterday it was PO238 map sensor voltage high, I cleared this yesterday to see what would happen today

Turned ignition on today and PO237 map sensor voltage low set, no PO238

Done the diagnostics for the 237 code  and everything checks out except map voltage is 0.5v ignition on not running or running, it does increase to around 1v to 1.6v if stalled in gear

I got 5.2v on orange which tells me the 5v supply is good, no other sensor codes set

no short  to earth on the other 2 wires or each other

I haven't disconnected the ecm plugs and checked continuity of these two

Fitted a quad about 2 to 3 months ago but I can't see that causing the problem, been working fine and still is

I'm going to order a Map sensor and was wondering if anyone has used a  STANDARD MOTOR PRODUCTS AS334  this is £59.85 from Rockauto or am I better ordering a Cummins part ?

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I am on my second  SMP MAP sensor. The first one lasted about 18 months. It failed while the VP was failing back in November. It was working fine up that moment. Coincidence or not I dont know. I did install another SMP as I have had good luck with there products thru the years. 

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Map sensor arrived from Rockauto last week, I got around to fitting it yesterday (not able to drive much here in the UK due to Lockdown)


I got the SMP map sensor and I don't see why but for the record it's a very strange size, the double hex peaks are milled off so while a 1,1/16th open end spanner is a perfect fit across the flats a 1,1/6th socket either single or double hex does not grip it.

1,1/16th is 26.99mm BUT 27mm double hex does not grip it, the only socket that will grip it is 27mm single hex, this grips the SMP map on the flats and not the peaks which just aren't there.

I have every socket size known to man including BSW and BSF and I checked every one I have eventually finding a 27mm single hex 1" drive socket that I reduced down to 1/2" drive.

This isn't the flat plug version as my truck is 98.5 so this is only relevant to the odd shaped plug map not the flat plug map

Cleared the code and all is good


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That's interesting.  I will look up what the dimensions are, but we have an "odd shape"  sensor like that in the US.  It was an oil pressure sensor.  I have a special socket from the late 1970's early 80's and that is what is stamped on the outside.  Most domestic oil pressure sensors (GM,Ford, Chrysler) used that same sensor shape.  But I know one of my import cars used the same thing... not sure if it was the Audi or the VW's....  man my memory sucks anymore...



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1 hour ago, Mopar1973Man said:

Need a 6 sided 1 1/16 socket. 


I got the very same sensor and no issues as long as you have that 6 sided socket.

I couldn't say as I didn't have one at home, I'm on this furlough deal so can't go into work under any circumstances and while I do have my work van at home it is unable to carry all my tools and stay under 3500kg gross,  I can say for sure a 1 1/16th double hex doesn't fit, 27mm is  0.1 of a mm less than 1 1/16th so we'll call that good on 6 sided

I posted it because 1 1/16th double hex is a common size for head bolts and I have several, I cannot for the life of me see why SMP made the thing with the peaks milled off

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