Aadam22

Hi
Trying to identify a 4266 fault and Iam a little confused as to what pins to check. Pin 1 on plug -return pump ground- Manual says to check resistance between PSM control module plug pin 1 and ground. See pictures. Plug pin 1 says -return pump ground- Confused-help.
Any help is greatly appreciated....thanks in advance.

Marv

You need to know what the "Ground Point of PSM" means.

From what I gather, the test is to determine if there is an open wire in the loom.

You could try checking the resistance between Pin 1 and the case of the PSM unit, assuming it is metal.

Then again, it might mean Pin 5, but I would expect them to simply say that.

Stephen Tinker

As Marv says above ^^^^^
It looks like pins #1, 4 & 5 are ground connection pins and therefore common with the chassis and the PSM module. There should be no resistance or open circuit between these pins and the chassis ground if I'm reading the fault diagnosis description correctly.

Aadam22

Thanks for the quick response. Very confusing, iam sure someone must know how to check this fault, and which pin’s to use. Uggg.

Aadam22

Thanks for the quick response. Yes very confusing, maybe the manual I have is wrong...iam sure someone out there must have diagnosed this problem and which pin ‘s to use. Maybe iam looking at this wrong, should be looking at highlight in blue.

Pin 1 is ground for return pump ground.

Aadam22

Hi.
‘Does this make sense to anyone.

Set the meter to ohm and connect the black wire to vehicle ground and red lead to pin 1

If you measure less than 5 ohms as described in the procedure the circuit is ok and the problem lies elsewhere

In order to measure resistance the ignition must be off. You are reading how much resistance is in the circuit. The plug will be off and not connected to the module therefore measuring the harness

Just a guess on my part - anything look wrong with my interpretation?

thanks.

Stephen Tinker

You are correct - you are measuring the ground cable resistance only. Grounds are usually not switched, so pulling the plug and measuring between the pin(s) and the PSM module (or the chassis) should give you a reading less than the 5 ohms stated. If its less than 5 ohms, great.... if its more than 5 ohms you have a high resistance (loose or badly connected connection), if you have an open circuit it means you have a broken or damaged ground wire.

Aadam22

Thanks again for the help. Verbiage in the diagnostic manual is a little confusing. For me anyway. Thanks for all the help, greatly appreciated.

cgfen

Hope you get this sorted out.
I'm confused too.
I did not think our cars has Porsche Stability Management.
Does PSM mean something else??

Stephen Tinker

Looking at the Porsche fault code diagrams, they are for a 996 Turbo..... I read this as being a specific electrical problem as apposed to being a GT3 issue.

Aadam22

Hi folks. Checked ohmmeter and got 4.9. To ground. Manual said <5 ohms this eliminates the cable.

Aadam22

What if it’s 5 ohms exactly???

powdrhound

Wrong manual. PSM nannies are only on a 996TT, not 996GT3.

Marv

Just how accurate is your meter and are your leads in good shape and when was the meter last calibrated?

Look for the problem elsewhere first.

Aadam22

PSM NANNIES...... NICE VERY HELPFUL.