P1402 Fault Code

I have a 2007 Sprinter, converted to a camper, that's only done 50,000 miles. Most of these have been on journeys at least of 50 miles.
It's recently started throwing up the P1402 code and although not going into complete Limp Mode, it has lost some power.

I have replaced the EGR Valve and the MAF but it has not made any difference to the van although it certainly has to my wallet!

Any suggestions as to what might be causing this fault?

Cheers,

Ralph

Just in case someone ever has this problem, I wanted to let you guys know I've eventually solved it.
The culprit was the Exhaust Pressure Sensor, I think sometimes called a Differential Pressure Sensor.

It's located underneath the van, immediately under the (right hand) driver's seat.

Not difficult to replace.


Ralph

What code reader were you using?

Just a simple OBD2 reader from eBay. This gave the code and looking around the internet, it pointed to the EGR valve, which I renewed, with no luck.
Further reading then led me to the MAF. Again, replaced with no results.
Only later did I see a mention on a site suggesting the Pressure Sensor. If I'd found this site first, I'd have replaced the Pressure Sensor as it's the cheapest in this trio of replacements!
Without a proper reader it was just trial and error, hence my first post.

RalphB said:

Without a proper reader it was just trial and error, hence my first post.

Click to expand...

Ya, that was what I was going to point out, i.e. a generic OBDII reader may lead one to replace components necessarily. P1402 in a universal sense means 'something to do with the EGR system, or maybe not' but the precise meaning can vary by manufacturer and I'm not sure what it means precisely for MB. A code reader than can display MB-specific codes would probably have been more valuable and might have helped to you to avoid shotgunnng (replacing EGR valve, then MAF sensor, then finally pressure transducer.) Or maybe not, but the point is that using a generic OBDII reader on a Sprinter can lead you astray as often as it can help. For anyone doing diagnostic work a scanner that can read MB-proprietary codes is a good investment, could probably be paid for in money saved by having the correct diagnosis sooner (for example an MD802 scanner costs half of an unneeded replacement EGR valve.)

I'm certainly not meaning to criticize your troubleshooting effort, just mentioning...

.

Hi'
I'm absolutely not feeling criticized and appreciate your comments!
In fact you've taught me something.
I thought my choice of scanners kind of quantum leaped between a universal OBD2 scanner to a Star type scanner costing lots of money.

So my next step will be to try and sell my old but functioning EGR and MAF and buy the type of scanner you suggest as it has to be better, if not infallible.

Cheers,

Ralph

No scanner is infallible, in fact even the best will not necessarily read out the exact problem. It's just a tool to provide clues and the experience of the mechanic does the rest. But at the very least you want a correct and complete set of clues, and that is what a more sophisticated scanner can provide.

RalphB said:

So my next step will be to try and sell my old but functioning EGR and MAF and buy the type of scanner you suggest as it has to be better, if not infallible.

Cheers,

Ralph

Click to expand...

On that note: if anyone on this forum would like to receive a used-but-probably-not-malfunctioning EGR and MAF, I'll be happy to send them mine for the cost of shipping.

I won't ever be buying another EGR, but will buy a GDE tune instead if the occasion arises.